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Supplement to the American Journal of Roentgenology

AJR March 2009, Vol. 192, No. 3, pp. S1–S64

LIFELONG LEARNINGFOR RADIOLOGY

Integrative Imaging

Three of the articles in this issue of AJR Integrative Imaging offer SAM and CME credits.

CME CreditThe American Roentgen Ray Society (ARRS) is accredited by

the Accreditation Council on Continuing Medical Education(ACCME) to sponsor continuing medical activities for physicians.

The ARRS designates this educational activity for a maxi-mum of 4.5 credits toward the AMA Physician’s RecognitionAward. Each physician should claim only those credits that heor she actually spent in the activity.

• Up to 1.5 CME credits may be claimed for Imaging of LungTransplantation: Self-Assessment Module.

• Up to 1.5 CME credits may be claimed for CT Virtual En-doscopy in the Evaluation of Large Airway Disease: Self-Assess-ment Module.

• Up to 1.5 CME credits may be claimed for Radiologic Signsin Thoracic Imaging: Case-Based Review and Self-AssessmentModule.These CME articles consist of two parts: one, the text and re-

lated images appearing in this supplement; and two, the self-eval-uation quiz, which is available online at www.arrs.org. You shouldread the articles, review the accompanying images and refer tothe articles referenced in this supplement, then complete the self-evaluation quiz. To obtain CME credit you must complete the self-evaluation quiz online. Visit www.arrs.org and go to the left-handmenu bar under Publications/Journals/SAM Articles. There is nocharge for ARRS members to participate in this program. Non-members pay a fee to access CME and SAM material.

Date of release: February 19, 2009Expiration date: February 18, 2012

Estimated time of completion: 4.5 hours

In compliance with the Essentials and Standards of the ACCME,authors of the CME activities in this publication are required to dis-close all relevant financial relationships with any commercialinterest to the ARRS. The ACCME defines “relevant financial re-lationships” as financial relationships in any amount occurringwithin the past 12 months that create a conflict of interest.

Drs. Agarwal, Attili,Chasen, Day, Dillon, Donnelly, Ep-stein, Holloway, Jan, Mueller, Ng, Parker, Patsios, Paul,Strother, Thomas, and Worrell, have all indicated that theyhave no commercial interests to disclose.

SAM and CME CreditImaging of Lung Transplantation: Self-Assessment Module. To

obtain 1 SAM credit and 1.5 CME credits, you must follow theinstructions on page SXX.

CT Virtual Endoscopy in the Evaluation of Large Airway Disease:Self-Assessment Module. To obtain 1 SAM credit and 1.5 CMEcredits, you must follow the instructions on page SXX.

Radiologic Signs in Thoracic Imaging: Case-Based Review andSelf-Assessment Module. To obtain 1 SAM credit and 1.5 CMEcredits, you must follow the instructions on page SXX.

Imaging of Lung Transplantation: Self-Assessment Module, CTVirtual Endoscopy in the Evaluation of Large Airway Disease: Self-Assessment Module, and Radiologic Signs in Thoracic Imaging:Case-Based Review and Self-Assessment Module are qualified bythe American Board of Radiology (ABR) in meeting the crite-ria for self-assessment toward the purpose of fulfilling require-ments in the ABR Maintenance of Certification. To obtainSAM credit, visit www.arrs.org and go to the left-hand menubar under Publications/Journals/SAM Articles.

CME and SAM Information

AJR Integrative Imaging


COVER ART CREDIT: Mani Puthuran

British Museum

COVER ARTWORK SUBMISSIONS

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AJR 2006;186:S135–155

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© American Roentgen Ray Society

Section Editor, AJR Integrative Imaging Felix S. Chew, MD, EdMSeattle, WA

Assistant Editors Susanna I. Lee, MD, PhDPierre D. Maldjian, MDCatherine C. Roberts, MD

Education Committee Chair Norman J. Beauchamp, MD

CME Liaison to the AJR Gary J. Whitman, MD

MOC Coordinating Committee Chair Jannette Collins, MD

MOC Coordinating CommitteeBreast Imaging Katherine A. Klein, MD

Liane Philpotts, MDCardiac Imaging Gautham P. Reddy, MDCritical Thinking John Eng, MD

Gastrointestinal Asra Khan, MDGeneral Content Stephen Chan, MD

Aine Kelly, MD Genitourinary Imaging Deborah A. Baumgarten, MD, MPH

Musculoskeletal Disease and Trauma Felix S. Chew, MD, Michael J. Tuite, MDNeuroradiology Pamela W. Schaefer, MD

Nuclear Medicine Darlene Metter, MDPediatric Imaging Beverly P. Wood, MD, MSEd, PhD

Pulmonary Imaging James G. Ravenel, MDVascular & Interventional Imaging Brian S. Funaki, MD

Ultrasound Teresita L. Angtuaco, MD

LIFELONG LEARNING FOR RADIOLOGYA supplement to the American Journal of Roentgenology Volume 192, No. 3, March 2009

Editor in Chief, AJR

Thomas H. Berquist, MDJacksonville, FL

Section Editors, AJR

Cardiopulmonary ImagingCharles S. White, MD

Gastrointestinal ImagingJoel G. Fletcher, MD

Genitourinary ImagingMukesh G. Harisinghani, MD

Health Care Policy and QualityHoward P. Forman, MD, MBA

Medical Physics and InformaticsG. Donald Frey, PhD

Musculoskeletal ImagingDonna G. Blankenbaker, MD

Neuroradiology and Head and Neck ImagingJames M. Provenzale, MD

Nuclear Medicine and Molecular ImagingKing C. Li, MD, MBA

Pediatric ImagingBeverly P. Wood, MD, MSEd, PhD

Vascular and Interventional RadiologyMatthew A. Mauro, MD

Women’s ImagingMarcia C. Javitt, MD

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S484 AJR:187, September 2006

1. Reviews and Self-Assessment ModulesAlthough these articles may have a variety of formats (see

specific types below), common elements include educational ob-jectives, multiple-choice self-assessment questions that refer di-rectly to the educational objectives, explanation of the correctand incorrect responses, and references. It is expected that somemultiple-choice questions may be case-based. Each illustrationshould have a detailed description, either in the legend or in thetext, and include the age, sex, and condition of the patient, aswell as a description of the technology used to produce the image(e.g., endoluminal 3D CTC image of 32-year-old man with…).

Author instructions: The review portion of the manuscriptshould have 5,000–10,000 words of text, 10–25 figure parts, andas many references as needed. The self-assessment portion shouldhave a least 10 four-option multiple-choice questions with com-plete solutions. The multiple-choice questions should have a sin-gle best response, and should be acceptable to the AmericanBoard of Radiology (ABR). The multiple-choice questions maybe used to introduce the case discussions, to assess comprehen-sion, or both. The solution to each multiple-choice questionshould explicitly state why each of the answer options is or is notthe best response, and should have at least one reference. Redun-dancy of information presented in the solutions with that pre-sented in the article text is to be expected.

Type 1. Case-based: This format consists of a set of educationalcase scenarios related by a theme. The case presentations consistof the clinical presentation, the rationale for imaging, a descrip-tion of the images, four-option multiple-choice questions, expla-nations of the best and incorrect responses, and concludingcommentary. The exact format depends on the particular case.The theme that relates the cases may be any combination ofanatomy, clinical presentation, pathophysiology, technique, de-mographics, etc. These articles should have a minimum of sixcase scenarios. The following is an example of a case-based re-view and SAM (Editor’s note: Fewer case scenarios were re-quired at the time this SAM was qualified by the ABR):

• Chew FS. Radiology of the Hands: Review and Self-Assess-ment Module. AJR 2005; 184[suppl]:S157–S168

Type 2. Evidence-based: This format consists of discussions ofone or more clinical management issues. The scientific evidencefor different courses of management is presented in the contextof illustrative case scenarios. These articles should have a mini-mum of six case scenarios. The following is an example of an ev-idence-based review and accompanying self-assessment module(Editor’s note: Fewer multiple choice questions were required atthe time this SAM was qualified by the ABR):

• Attili AK, Cascade PN. CT and MRI of Coronary Artery Dis-ease: Evidence-Based Review. AJR 2006; 187[suppl]: S483–S499

• Attili AK, Foral JM, Schoepf J, Cascade PN, Chew FS. CTand MRI of Coronary Artery Disease: Self-Assessment Mod-ule. AJR 2006; 187[suppl]:S500–S504

Type 3. Pictorial essay (clinically or pathophysiology-based):This format consists of an exposition on a clinically or patho-physiology-based topic with extensive illustrations. The follow-ing is an example of a pictorial review and self-assessmentmodule (Editor’s note: Fewer multiple-choice questions were re-quired at the time this SAM was qualified by the ABR):

• Poon CS, Chang J-K, Swarnkar A, Johnson MH, Wasenko J.Radiologic Diagnosis of Cerebral Venous Thrombosis: Picto-rial Review. AJR 2007; 189[suppl]:S64–S75

• Poon CS, Chew FS. Radiologic Diagnosis of CerebralVenous Thrombosis: Self-Assessment Module. AJR 2007;189[suppl]:S76–S78

Type 4. Review article: This format consists of a traditional re-view article with a large number of references. Illustrative casesand multiple-choice questions may be used to introduce or reviewtopics. The following is an example of a review article and self-as-sessment module (Editor’s note: Fewer multiple-choice questionswere required at the time this SAM was qualified by the ABR):

• Momeni AK, Roberts CC, Chew FS. Imaging of Chronic andExotic Sinonasal Disease: Review. AJR 2007; 189[suppl]: S35–S45

• Momeni AK, Roberts CC, Chew FS. Imaging of Chronicand Exotic Sinonasal Disease: Self-Assessment Module.AJR 2007; 189[suppl]:S46–S48

Type 5. Self-assessment module without accompanying review:This format consists of educational objectives, a list of requirededucational activities that are external to the SAM itself (such aspublished articles or Web content), 10 or more multiple-choicequestions that refer to the educational objectives and activities,and complete solutions that explain each answer option and pro-vide references.

The following is an example of a self-assessment module with-out accompanying review (Editor’s note: Fewer multiple-choicequestions were required at the time this SAM was qualified bythe ABR):

• Ko JP, Roberts CC, Berger WG, Chew FS. Imaging Evalu-ation of the Solitary Pulmonary Nodule: Self-AssessmentModule. AJR 2007; 188[suppl]:S1–S4

2. Radiological ReasoningThese are case presentations that step the reader through an

expert’s analysis of a difficult case. The case is presented progres-

Instructions for AuthorsA complete set of AJR Instructions for Authors, including information about figure processing and electronic submission requirements, canbe found at www.arrs.org.

AJR Integrative Imaging submissions should follow the formats outlined below.



S485 AJR:187, March 2006

sively, with the expert’s thought process described in detail. Con-cluding comments tie up loose ends and provide references andadditional relevant factual material. Clinical reasoning presenta-tions should fit on approximately five journal pages. The title ofthe article should reflect the clinical or imaging presentation, notthe specific pathologic diagnosis. The abstract should include thediagnosis and the take-home message of the article.

Author instructions: 2,000–4,000 words, NOT including themultiple choice questions and solutions, 5–10 figure parts. Threevoices: case presenter, expert discussant, and expert commenta-tor. Do not include a review of the literature because these may befound elsewhere (e.g., textbooks and actual review articles). Eacharticle should be followed by five four-option multiple-choicequestions that will be used to assess comprehension. Each of thebest and non-best responses should be explicitly explained in thesolutions, and each solution should have at least one reference.

Radiological reasoning articles are often used as required read-ing for self-assessment modules (see SAM Type 5, above), there-fore, authors of radiological reasoning manuscripts are stronglyencouraged to submit a companion self-assessment modulemanuscript at the same time. The following is an example of a ra-diological reasoning article and accompanying self-assessmentmodule (Editor’s note: Fewer multiple choice questions were re-quired at the time this SAM was qualified by the ABR):

• Liu PT. Radiological Reasoning: Acutely Painful SwollenFinger. AJR 2007; 188:[suppl]S13–S17

• Roberts CC, Liu PT, Chew FS. Imaging Evaluation of Ten-don Sheath Disease: Self-Assessment Module. AJR 2007;188:S10–S12

3. Teaching FileTeaching file cases are standard cases that are well illus-

trated, typically with an interesting twist. Unlike case reports,

which seek to extend the frontiers of knowledge, teaching filecases are intended as exemplars of known appearances and pre-sentations of disease, with the goal of educating the reader. Thestandard presentation includes clinical history, clinical images,radiologic description, focused differential diagnosis, final diag-nosis, and commentary. An abstract should be prepared thatprovides an educational objective and a conclusion. The title ofthe article should reflect the clinical or imaging presentationrather than the specific pathologic diagnosis. Authors shouldprovide two four-option multiple-choice questions with com-plete solutions. Each of the best and non-best responses shouldbe explicitly explained in the solutions, and each solutionshould have at least one reference. Authors will need to provideindexing terms and coding.

Teaching file cases should be 1,000–2,000 words, NOT in-cluding the multiple-choice questions and solutions, and typi-cally no more than eight figure parts. Some teaching filemanuscripts may be selected for publication as Web exclusives.Teaching File cases are often used as required reading for self-assessment modules (see SAM Type 5, above), therefore, teach-ing file manuscripts that are amenable to such use or areaccompanied by a companion self-assessment module manu-script are much more likely to receive serious consideration.The following is an example of a teaching file article and ac-companying self-assessment module (Editor’s note: Fewer mul-tiple choice questions were required at the time this SAM wasqualified by the ABR):

• Sutcliffe JB III, Bui-Mansfield LT. AJR Teaching File: In-termittent Claudication of the Lower Extremity in a YoungPatient. AJR 2007; 189[suppl]:S17–S20

• Chew FS, Bui-Mansfield LT. Imaging Popliteal Artery Dis-ease in Young Adults with Claudication: Self-AssessmentModule. AJR 2007; 189[suppl]:S13–S16



Table of Contents

Imaging of Lung Transplantation: Review.. ..............................................................SXXNg YL, Paul N, Patsios D, et al; DOI:10.2214/AJR.07.7061

Imaging of Lung Transplantation: Self-Assessment Module..................................SXXNg YL, Paul N, Patsios D, et al.; DOI:10.2214/AJR.07.7130

CT Virtual Endoscopy in the Evaluation of Large Airway Disease: Review. ...............SXXThomas BP, Strother MK, Donnelly EF, Worrell JA; DOI:10.2214/AJR.07.7077

CT Virtual Endoscopy in the Evaluation of Large Airway Disease:Self-Assessment Module. .......................................................................................SXXThomas BP, Strother MK, Donnelly EF, Worrell JA; DOI:10.2214/AJR.07.7129

Radiologic Signs in Thoracic Imaging: Case-Based Review and Self-Assessment Module. .......................................................................................SXXParker MS, Chasen MH, Paul N; DOI:10.2214/AJR.07.7081

AJR Teaching File: Right Atrial Mass in a Woman with Dyspnea on Exertion. .........SXXHolloway BJ, Agarwal PP; DOI:10.2214/AJR.07.7066

AJR Teaching File: Right Atrial Mass in a Woman with Uterine Fibroids..................SXXJan S, Dillon EH, Epstein NF; DOI:10.2214/AJR.07.7080

AJR Teaching File: Asymptomatic Man with Giant Negative T Waves on ECG..........SXXAttili A, Mueller GC, Day SM; DOI:10.2214/AJR.07.7116

Author Correction.......................................................................................................SXX

LIFELONG LEARNING FOR RADIOLOGYA supplement to the American Journal of Roentgenology Volume 192, No. 1, March 2009

Integrative Imaging

1.5 CME1.0 SAM

1.5 CME1.0 SAM

1.5 CME1.0 SAM

S1 AJR:192, March 2009


LIFELONG LEARNING FOR RADIOLOGY

Imaging of Lung Transplantation: ReviewYuen Li Ng1, 2, Narinder Paul3, Demetris Patsios3, Anna Walsham4, Tae-Bong Chung3, Shaf Keshavjee5, Gordon Weisbrod3

Keywords: lung transplantation

DOI:10.2214/AJR.07.7061

Received November 29, 2007; accepted after revision February 19, 2008.1CT Unit, Jubilee Wing, Department of Clinical Radiology, Leeds General Infirmary, Leeds LS1 3EX, West Yorkshire, United Kingdom.2Present address: Department of Diagnostic Radiology, Singapore General Hospital, Outram Rd., Singapore 169608. Address correspondence to Y. L. Ng ([email protected]).3Joint Department of Medical Imaging, Thoracic Division, University Health Network and Mount Sinai Hospital, Toronto General Hospital, Toronto, ON, Canada.4Department of Clinical Radiology, Hope Hospital, Manchester, United Kingdom.5Division of Thoracic Surgery and Toronto Lung Transplant Program, Toronto General Hospital, Toronto, ON, Canada.

AJR 2009;192:SXX–SXX 0361–803X/09/1923–SX © American Roentgen Ray Society

OBJECTIVELung transplantation is an established treatment for end-

stage pulmonary disease. Complications of lung transplan-tation include airway stenosis and dehiscence, reimplanta-tion response, acute rejection, infection, posttransplantation lymphoproliferative disorder, and bronchiolitis obliterans syndrome. The incidence of graft rejection and airway anastomosis experienced in the early years of lung trans-plantation have been significantly reduced by advances in immunosuppression and surgical techniques. Infection is currently the most common cause of mortality during the first 6 months after transplantation, whereas chronic rejec-tion or obliterative bronchiolitis is the most common cause of mortality thereafter. This article reviews the radiologic findings of different surgical techniques as well as the com-mon early and late complications of lung transplantation.

CONCLUSIONRadiology plays a pivotal role in the diagnosis and man-

agement of complications of lung transplantation. Ad-vancements in surgical technique and medical therapy in-fluence the spectrum of expected radiologic findings. Familiarity with the radiologic appearances of common surgical techniques and complications of lung transplanta-tion is important.

IntroductionThe first successful isolated single-lung transplantation

procedure was performed by the Toronto General Hospital group at the University of Toronto in 1983 [1]. Lung trans-plantation has since become an established treatment for end-stage pulmonary disease [2]. The registry of the Inter-national Society for Heart and Lung Transplantation (ISHLT) recorded an all-time high of 2,169 lung transplantations in 2005 [3]. The main indications for lung transplantation in the 18 months before this writing were chronic obstructive pul-monary disease (COPD, 38%), idiopathic pulmonary fibrosis

(IPF, 19%), cystic fibrosis (16%), and α1-antitrypsin defi-ciency emphysema (8%) (Table 1). The reported survival rates from January 1994 to June 2005 were 87% at 3 months, 78% at 1 year, 62% at 3 years, 50% at 5 years, and 26% at 10 years [3]. Overall, sepsis was the predominant cause of death in the first 6 months after transplantation, whereas chronic graft failure was the main cause of death after 6 months [2].

Surgical TechniquesSingle-lung transplantation is usually performed through

a posterolateral thoracotomy. On the other hand, bilateral lung transplantation is generally performed through a transverse thoracosternotomy involving bilateral sequen-tial single-lung transplantation [2]. The technique of en bloc double-lung transplantation with tracheal anastomosis is now rarely performed because of the increased rate of anastomotic dehiscence.

Bilateral lung transplantation accounted for 63% of lung transplantation procedures in 2005 [3]. Bilateral lung trans-plantation is usually performed for chronic pulmonary sep-sis such as cystic fibrosis and bronchiectasis (Table 1). It is also the dominant procedure for primary pulmonary hyper-tension. Bilateral lung transplantation for both COPD and IPF has increased in recent years. This trend may be ex-plained by the higher overall survival rate after bilateral transplantation, by the increased lung function to buffer complications, and by institutional preferences and prac-tices. The lung transplantation program at our institution prefers the use of bilateral lung transplants [2, 3].

Airway anastomotic dehiscence was one of the major ob-stacles to success in the early years of lung transplantation [4]. The early surgical techniques aimed to reduce the inci-dence of bronchial dehiscence by improved healing of the anastomoses using intercostal muscle, pericardium, or omentum to wrap the end-to-end bronchial anastomoses [5, 6]. However, the development of significant complications such as diaphragmatic hernias associated with the omental

Ng et al.


A

C

Fig. 1—Bronchial anastomosis.A, Schematic diagram shows end-to-end and “telescope” anastomoses.B, 41-year-old woman who underwent bilateral lung transplantation in 1980s. CT scan shows area of fat attenuation (asterisk) in thorax, representing omentum used to wrap bronchial end-to-end anastomoses.C and D, Axial (C) and coronal (D) CT reformations show normal posttransplantation appearance of telescope anastomoses. Note bronchial overlap; smaller bronchus is “telescoped” into larger bronchus. Internal margin of anastomosis is not sutured and may result in endoluminal flap (arrowhead, D).

B

D

TABLE 1: Distribution of Diagnoses and Procedures Among Adult Lung Transplant Recipients (January 1995 to June 2006) [3]

Diagnosis Single Lung Transplants Double Lung Transplants Total

Chronic obstructive pulmonary disease or emphysema 4,305 (52) 2,225 (24) 6,530 (38)

Idiopathic pulmonary fibrosis 2,193 (26) 1,217 (13) 2,410 (19)

Cystic fibrosis 167 (2.0) 2,722 (29) 2,889 (16)

Alpha1-antitrypsin deficiency emphysema 626 (7.5) 795 (8.5) 1,421 (8.1)

Primary pulmonary hypertension 65 (0.8) 575 (6.2) 640 (3.6)

Sarcoidosis 178 (2.1) 260 (2.8) 438 (2.5)

Bronchiectasis 30 (0.4) 473 (5.1) 503 (2.6)

Lymphangioleiomyomatosis 59 (0.7) 116 (1.2) 175 (1)

Cancer 7 (0.1) 12 (0.1) 19 (0.1)

Note—Data are numbers (%) of patients. Reprinted with permission from [3].

AJR:192, March 2009 S3

Lung Transplantation

Bronchial dehiscence is the most common airway complica-tion in the early postoperative period, affecting 2–3% of cases [2, 6, 12] and typically occurring 2–4 weeks after transplanta-tion [6, 9, 10]. CT typically shows the presence of extraluminal gas and, occasionally, the focal bronchial wall defect that is pathognomonic of this condition [14] (Fig. 2). Indirect signs of bronchial dehiscence include the presence of a new or persis-tent air leak, pneumothorax, and pneumomediastinum.

Bronchial stricture formation is seen in approximately 10% of cases; it occurs later in the postoperative period, an average of 3 months after surgery [6, 9, 10]. There is thought to be an increased incidence of stricture formation with the use of the telescope anastomosis technique [8]. CT with multiplanar re-constructions is helpful in depicting strictures and webs and is

wrap technique [6] encouraged the refinement of surgical techniques and the development of the “telescope tech-nique” (Fig. 1), which does not require a wrap procedure [7]. With further advances in surgical technique and donor preservation, end-to-end anastomoses without a wrap pro-cedure have been performed with good success [2, 8].

The telescope technique is preferentially used in our in-stitution when there is bronchial size discrepancy. The smaller bronchus is intussuscepted into the larger bronchus, which then helps to maintain an adequate bronchial lumen and act as an anastomotic stent. When bronchial size is equivalent, end-to-end anastomosis is performed [2]. After bronchial anastomosis, the pulmonary artery and vein anastomoses are performed. The bronchial arterial circula-tion is not reestablished during transplantation, and rear-terialization via recipient bronchial arteries requires an es-timated 2–4 weeks after surgery [6, 9].

Airway ComplicationsThe incidence of airway complications has decreased

with improved surgical and donor preservation techniques, immunosuppression, and posttransplantation surveillance [4, 8, 10]. Airway complications have been estimated to oc-cur in approximately 5–15% of lung transplants. [4, 6, 9, 10]. The healing of bronchial anastomoses relies on healthy retrograde collateral perfusion from the pulmonary arterial circulation in the initial postoperative period because bron-chial arteries are not reanastomosed during transplantation [6, 11]. A suboptimal vascular supply predisposes to isch-emia and subsequent ulceration, leading to bronchial dehis-cence, stricture formation, and bronchomalacia [6, 12]. In-fection and rejection may also play a role.

Airway complications such as bronchial dehiscence and stricture are usually diagnosed by bronchoscopy. However, CT is valuable and is more sensitive than chest radiography in the diagnosis of airway complications [13].

Fig. 2—Bronchial dehiscence in 28-year-old woman 11 days after bilateral lung transplantation. Patient developed persistent bilateral pneumothoraces (curved arrows) despite bilateral thoracostomy drains (arrowheads). Cause was re-vealed on CT, which shows focal defect at right bronchial anastomosis and ex-traluminal air (straight arrow). Note also left lower lobe pneumonia causing consolidation and atelectasis.

A

Fig. 3—Bronchial stricture in 36-year-old man 6 weeks after bilateral lung transplantation.A and B, Low-dose (50-mA) axial CT scan (A) and coronal reconstruction (B) show focal tight stenosis at left bronchial anastomosis (arrows).

B

Ng et al.


particularly useful in assessing the extent of bronchial stenos-es in order to plan bronchoscopic stent insertion [15] (Fig 3).

Vascular ComplicationsVascular anastomotic stenoses, which are more common

at the arterial anastomoses, are rare, occurring in fewer than 4% of cases [16]. The risk of pulmonary infarction is greatest in the immediate postoperative period because the transplanted lung does not have an alternative bronchial blood supply. Perfusion scintigraphy may aid in making the diagnosis. The prognosis is usually dismal, but successful outcomes have recently been reported with angioplasty and stent insertion [8].

Mechanical ComplicationsSize mismatch between donor lung and recipient thoracic

cavity may cause mechanical complications. Most centers will accept size differences of within 25% [17, 18]. If the do-nor lung is too large for the recipient, distortion of airways and atelectasis may occur, with retained secretions and sec-ondary infections. This may lead to scarring. The oversized lung graft may be intraoperatively reduced to match the ca-pacity of the recipient. If the donor lung is too small for the recipient, graft hyperexpansion may lead to hemodynamic compromise, limited exercise tolerance, or frank pulmonary hypertension, all because of an inadequate vascular bed [17]. In patients with emphysema who undergo single-lung trans-plantation, the small graft may be compressed by the em-physematous native lung, resulting in restrictive pulmonary function [18]. Lung volume reduction surgery may be per-formed during the transplantation procedure.

Pulmonary torsion is a rare but serious complication that may occur in the immediate postoperative period. Imaging features of pulmonary torsion are related to the torquing of the hilar structures, the airway, and the vasculature, and in-clude a collapsed lobe (due to airway compromise) or an ex-pansile consolidated lobe (due to hemorrhagic infarction) in an atypical location [19]. Other features that may be present are bronchial cutoff, inappropriate hilar displacement associ-ated with an atelectatic lobe, abnormal position of pulmo-nary vasculature and bronchi, rapid opacification of a lobe or

A

Fig. 4—Pneumothorax after transbronchial biopsy in 45-year-old man. This patient experienced right pleuritic pain after surveillance bronchoscopy and trans-bronchial biopsy.A, Immediate chest radiograph shows localized right basal pneumothorax (asterisk).B, Subsequent CT scan confirms localized right basal hydropneumothorax associated with right lower lobe atelectasis and bronchiectasis.

B

Fig. 5—Pleural empyema and hematoma in 49-year-old man whose condition deteriorated clinically 8 days after bilateral lung transplantation. CT scan re-veals focal fluid collection (single asterisk) in left anterior hemithorax contain-ing gas, suggestive of empyema. Note also large focal collection in right basal hemithorax with higher-attenuation hematoma (double asterisks). Findings were confirmed at thoracotomy.



lung, and change in position of an opacified lobe on sequential radiographs. Once pulmonary torsion is suspected, immediate surgery is indicated to avoid death from lobar infarction.

Pleural ComplicationsPleural complications are seen in 22–34% of patients af-

ter transplantation [20, 21]. Bilateral-lung and heart–lung transplantations frequently result in a single communicat-ing pleural space. Therefore, fluid and gas collections are often bilateral [8].

Pneumothorax is the most common pleural complica-tion; it usually resolves with the insertion of thoracostomy

drains [8, 21]. New, persistent, or enlarging pneumothoraces should prompt further investigations to elucidate the cause of the air leak (Fig. 2). Pneumothorax may also occur after transbronchial biopsy (Fig. 4).

Pleural effusions develop in almost all patients because of increased capillary permeability and impaired lymphatic clearance of the transplanted lung [12, 20]. They are usu-ally self-limiting and resolve within 2 weeks. Persistent or delayed effusions suggest complicated effusions such as em-pyema, organized hematoma, rejection, and posttransplan-tation lymphoproliferative disorder (PTLD). Empyema oc-curs in approximately 4% of patients and may affect both hemithoraces, with potential disastrous consequences [8, 20] because it is the only pleural complication associated with an increased mortality rate [21]. Therefore, empyema should be excluded in the presence of a new or enlarging pleural effusion (Fig. 5).

Pulmonary Parenchymal ComplicationsMany pulmonary parenchymal complications after lung

transplantation have nonspecific radiologic findings. Corre-lation with the time interval from transplantation is helpful to narrow the differential diagnoses (Fig. 6). Clinical corre-lation and bronchoscopy with transbronchial biopsy are also often required.

Reimplantation ResponseReimplantation response, also known as reperfusion ede-

ma, is a form of noncardiogenic pulmonary edema that oc-curs in more than 95% of patients [22] (Fig. 7). It frequent-ly begins by postoperative day 1, is always present by day 3, peaks by day 4 or 5, and resolves by day 10 [8, 11]. Persis-tence beyond the first week suggests infection or acute re-jection. Reimplantation response is usually diagnosed after

2 y

1 y

6 mo

3 mo

4 wks

Day 7

Day 0 Reimplantation response

Bacterial infectionAcute rejection

Fungal infection

Viral infection

PTLD

Obliterative bronchiolitis

Recurrent disease

Upper lobe fibrosis

Fig. 6—Diagram shows typical time course for onset of pulmonary parenchymal complications after lung transplantation. PTLD = posttransplantation lympho-proliferative disorder.

A

Fig. 7—Reimplantation response in 33-year-old woman 2 days after bilateral lung transplantation.A, Chest radiograph shows typical features of reimplantation response: bilateral perihilar and basal consolidation.B, CT scan shows bilateral patchy ground-glass opacities and septal thickening in addition to consolidation.

B

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exclusion of left ventricular failure, fluid overload, trans-plant rejection, and infection [22, 23].

Chest radiography and CT typically show bilateral peri-hilar and basal air-space consolidation [22]. The pathogen-esis is probably multifactorial: increased vascular permea-bility due to ischemia and subsequent reperfusion, lymph atic interruption, lung denervation, decreased surfactant pro-duction, and surgical trauma [12].

Acute RejectionAcute rejection usually occurs within the first 3 weeks, typi-

cally between postoperative days 5 and 10 [8] (Fig. 8). Most patients experience two or three significant rejection episodes in the first 3 months after transplantation [12]. Repeated epi-sodes of acute rejection are associated with an increased risk of chronic rejection (i.e., bronchiolitis obliterans syndrome) [24].

The radiographic features may be similar to those of re-implantation response and infection. The presence of new,

persisting, or progressive perihilar and basal opacities or pleural effusions with septal lines 5–10 days after trans-plantation without other signs of left ventricular failure is suggestive of acute rejection [8, 25]. CT findings include ground-glass opacities, interlobular septal thickening, nod-ules, consolidation, and volume loss. Ground-glass opacities are often patchy and localized in mild rejection but wide-spread in severe rejection [26]. However, CT has limited ac-curacy in the diagnosis or grading of severity of acute re-jection [24].

Patients may be asymptomatic or may present with dysp-nea, fever, leukocytosis, and decreased exercise tolerance. Investigations reveal a decrease in arterial oxygenation and forced expiratory volume in 1 second (FEV1). The most use-ful feature is the dramatic clinical and radiographic re-sponse to corticosteroids and increased immunosuppression [8, 23]. Transbronchial biopsy is often performed to confirm the diagnosis and to exclude infection [8].

A

Fig. 8—Acute rejection diagnosed on transbronchial biopsy in 51-year-old woman 7 days after bilateral lung transplantation.A, Portable chest radiograph shows nonspecific pulmonary opacities in perihi-lar, mid, and lower lung bilaterally.B and C, CT images show bilateral patchy ground-glass opacities, consolida-tion, and interlobular septal thickening (arrows, B).

B C



InfectionInfection is the most common complication after trans-

plantation and is a major cause of morbidity and mortality [2]. Patients have increased susceptibility to infection be-cause of immunosuppression, lung denervation and loss of the cough reflex, impaired mucociliary function, and lym-phatic drainage [8, 27].

Bacterial infections predominate in the first 4 weeks after transplantation; viral infections are generally not seen until

the following month. Fungal infections can occur at any pe-riod after transplantation. Pneumocystis pneumonia is now uncommon because of the routine use of trimethoprim-sulfamethoxazole prophylaxis [12].

Bacterial InfectionBacterial infections account for at least 50% of all infec-

tions [11]. The incidence is highest in the first month, but re-mains a significant complication throughout the patient’s life

A

Fig. 9—Infections with Aspergillus organisms in two patients.A, 26-year-old man developed aspergillosis 1 month after bilateral lung transplantation. CT scan shows multiple nodules (curved arrows), some with surrounding ground-glass halo sign (arrowheads) and cavitation (straight arrow).B, CT scan in 37-year-old man 3 weeks after bilateral lung transplantation shows patchy ground-glass opacities in left lower lobe. Culture of bronchial washings was positive for Aspergillus organisms.

B

A

Fig. 10—Cytomegalovirus pneumonia in seropositive 44-year-old man after bilateral lung transplantation.A, Chest radiograph shows nonspecific bilateral basal patchy and hazy opacities.B, CT scan shows bilateral patchy ground-glass attenuation and micronodules.

B

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[8, 27]. Death is unusual in the immediate postoperative pe-riod because of the wide use of broad-spectrum antibiotics.

The most common causative organisms are gram-negative bacilli such as Klebsiella organisms, Pseudomonas aeruginosa, and Enterobacter cloacae. Gram-positive organisms such as Staphylococcus aureus are also observed [8, 11]. In patients with cystic fibrosis, the presence of Burkholderia cepacia is associated with severe postoperative infections and reduced survival rates [2].

Radiologic features are similar to those of nontransplant patients: lobar or multifocal consolidation, ground glass opacity, cavitation, and lung nodules [8, 27].

Fungal InfectionFungal infections, most commonly Candida and Asper-

gillus organisms, usually occur between 10 and 60 days af-ter transplantation [27]. They are less common but are as-sociated with a higher mortality rate than viral infections [8]. Candida species frequently colonize the airways, but in-vasive pulmonary infection is uncommon.

Aspergillosis is more prevalent in lung transplantation pa-tients than in other immunocompromised patients. Locally invasive or disseminated infection with Aspergillus organisms accounts for 2–33% of infections after lung transplantation and 4–7% of all lung transplantation deaths [27]. Aspergillus organisms can cause indolent pneumonia or fulminant angio-invasive infection with systemic dissemination (Fig. 9). CT commonly reveals a combination of ill-defined nodules, cavi-tary opacities, consolidation, and ground-glass opacity [27]. Symptoms are nonspecific and include fever, cough, pleuritic chest pain, and hemoptysis [8].

Aspergillus infections in the airway are seen in 5% of pa-tients, mostly in the first 6 months. They are usually asymp-tomatic and are detected on surveillance bronchoscopy. Such an infection may cause ulcerative tracheobronchitis that is usually radiologically occult and can lead to bron-chial dehiscence, stenosis, or bronchomalacia [8].

Viral InfectionCytomegalovirus (CMV) is the second most common

cause of pneumonia in lung transplantation patients and is the most common opportunistic infection [8] (Fig. 10). CMV pneumonia most commonly occurs between 1 and 12 months, with a peak incidence at 1–4 months [27].

Chest radiographs may be normal or may show diffuse parenchymal haziness or reticulonodular interstitial opaci-ties. CT findings include areas of ground-glass attenuation, micronodules, consolidation, reticulation, and small pleural effusions [8, 27].

Patients may be asymptomatic or develop fulminant pneumonia. Clinical manifestations include dyspnea, fever, cough, and malaise [12]. CMV pneumonia is associated with an increased risk of superadded bacterial and fungal infec-tions as well as the development of bronchiolitis obliterans syndrome. Diagnosis can be made by bronchoalveolar la-vage and transbronchial biopsy.

Primary infection occurs in CMV-seronegative recipients who receive a graft from a seropositive donor. Infection de-velops in more than 90% and is serious in 50–60% of cases [27]. Thus, CMV matching between donor and recipient is performed whenever possible. Secondary infection develops from reactivation of a latent virus after immunosuppres-

A

Fig. 11—Posttransplantation lymphoproliferative disorder (PTLD) in 26-year-old man 4 months after bilateral lung transplantation.A, Multiple lung nodules were detected incidentally on surveillance chest radiograph.B, CT scan shows multiple nodules with surrounding halo of ground glass (arrows). Percutaneous CT-guided biopsy confirmed diagnosis of PTLD.

B



sion or from infection with a different CMV strain and is usually less serious than the primary infection [8].

Other viral agents include herpes simplex virus, adenovi-rus, and respiratory syncytial virus.

Posttransplantation Lymphoproliferative Disorder

PTLD is a spectrum of diseases that vary from a histo-logically benign polyclonal lymphoid proliferation to ag-gressive high-grade lymphoma [28]. It may manifest from 1 month to several years after transplantation but tends to

occur within the first year, peaking at 3–4 months [23] (Fig. 11). The incidence is approximately 5% (range, 1.8–20%), and it is more common with lung transplantation than with other solid organ transplantations [11, 28]. The variability in the incidence probably reflects differences in immuno-suppression, ages of the study population, rates of Ebstein-Barr viral (EBV) infections, and CMV prophylaxis.

Radiographically, PTLD usually manifests as solitary or multiple pulmonary nodules or masses [28]. Extrapulmo-nary involvement—hilar or mediastinal adenopathy, thy-mic enlargement, pleural effusions, and pericardial mass-

A

C

Fig. 12—Obliterative bronchiolitis in two patients.A and B, Chest radiograph (A) in 35-year-old woman 9 months after bilateral lung transplantation shows decreased vascular markings and increased lung volumes. CT scan (B) shows minor bronchial dilatation and mosaic attenuation. Transbronchial biopsy revealed obliterative bronchiolitis.C and D, Inspiratory (C, 50 mAs) and expiratory (D, 20 mAs) CT scans show bronchial dilatation and air trapping in right lower lobe in 45-year-old man with known obliterative bronchiolitis.

B

D

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S10 AJR:192, March 2009

es—is less common [11]. Clinical manifestations include low-grade fever, lethargy, and weight loss. Patients may also be asymptomatic.

PTLD is thought to be secondary to B-lymphocyte pro-liferation in response to EBV infection [11]. It is more com-

monly seen in EBV-seronegative recipients who receive an EBV-seropositive donor lung. Aggressive immunosuppres-sion regimens are also thought to be a cause [28]. Most cas-es respond to antiviral agents (e.g., acyclovir) and a reduc-tion or cessation of immunosuppressive therapy.

A

Fig. 13—Recurrent disease in three patients.A, Recurrent disease in 52-year-old woman 2 years after bilateral lung trans-plantation for sarcoidosis. CT scan shows nonspecific opacities in right lower lobe; transbronchial biopsy revealed noncaseating granulomas.B, 47-year-old woman with lymphangioleiomyomatosis (LAM) underwent bilat-eral lung transplantation. She developed chylothorax (arrow indicates fat–fluid level) and retroperitoneal lymphadenopathy, which proved at histology to be recurrent LAM.C, 58-year-old woman underwent bilateral lung transplantation 18 months ear-lier for multifocal bronchioloalveolar carcinoma. CT scan shows multiple nod-ules. Transbronchial biopsy confirmed recurrent disease.

B

C

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Obliterative BronchiolitisObliterative bronchiolitis is thought to be a manifesta-

tion of chronic rejection, affecting up to 50% of patients (Fig. 12). It is a major source of morbidity and mortality and is now the greatest limitation to long-term survival af-ter lung transplantation [2, 8, 11]. It usually develops with-in 6–18 months after transplantation but may occur as early as the second month. Significant association with pre-vious multiple episodes of acute rejection and CMV pneu-monia has been reported. Other potential risk factors in-clude other lung infections, gastroesophageal reflux, and human leukocyte antigen mismatching [29].

Obliterative bronchiolitis is a histologic diagnosis; chang-es affect the small airways in a patchy distribution. Trans-bronchial biopsy may not be diagnostic, particularly in the early stages [30]. Therefore, the disorder is frequently diag-nosed clinically, using the term “bronchiolitis obliterans syndrome,” on the basis of an otherwise unexplained de-cline in lung function [29]. Patients generally present with a cough and worsening dyspnea [11].

The chest radiograph may be normal or may show atten-uated pulmonary vessels, bronchial cuffing, subsegmental atelectasis, and irregular linear opacities [13, 31]. Lung vol-umes can be normal or mildly increased. CT typically shows bronchial dilatation, bronchial wall thickening, and mosaic attenuation that are most marked in the lower lobes [31]. Air trapping is frequently depicted on expiratory CT in pa-tients with obliterative bronchiolitis and can also be seen on inspiratory CT in areas of lower attenuation with attenuat-ed pulmonary vessels. However, the presence of air trap-

A

Fig. 14—56-year-old man who developed bilateral upper lobe fibrosis 2 years after bilateral lung transplantation.A, Chest radiograph shows bilateral upper lobe reticular opacities and volume loss.B, CT scan shows coarse reticulation, architectural distortion, traction bronchiectasis (arrowhead ), and honeycombing (arrow).

B

ping is of limited sensitivity for the early diagnosis of oblit-erative bronchiolitis [32].

Recurrent DiseaseRecurrent disease in the transplanted lung is uncommon,

affecting approximately 1% of recipients. Sarcoidosis, lymph-angioleiomyomatosis, bronchioloalveolar carcinoma, and Langerhans cell histiocytosis have been reported to recur in the transplanted lung [8, 33]. The radiologic features of re-current disease in the donor lung are similar to those of the original disease, but they may mimic other posttransplanta-tion complications such as infection, rejection, and PTLD.

Sarcoidosis is the most commonly reported disease to recur, with a frequency of 35% [34] (Fig. 13A). Recurrence of sarcoi-dosis has been reported as early as 2 weeks and as late as 2 years after transplantation. It is an incidental finding at trans-bronchial lung biopsy in most cases. Transbronchial biopsy shows multiple noncaseating giant cell epithelioid granulomas. Because granulomas can also be seen with mycobacterial or fungal infection, it is important to exclude these diagnoses. A negative transbronchial lung biopsy does not exclude recur-rent sarcoidosis because of the patchy nature of the disease.

Patients who have undergone lung transplantation for lymphangioleiomyomatosis have increased morbidity and mortality due to complications related to their underlying disease—for example, native lung pneumothorax, chylotho-rax, chylous ascites, hemorrhagic renal angiomyolipomas, and recurrence of disease—from 1 to 5 years after transplan-tation [34] (Fig. 13B).

Recurrence of bronchioloalveolar carcinoma has occurred in approximately 50% of patients who survive the trans-

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S12 AJR:192, March 2009

plantation [33] (Fig.13C). Recurrence is usually limited to a transplant graft and is slow-growing despite immunosup-pression. Lung transplantation for the treatment of multi-focal bronchioloalveolar carcinoma is not widely established, and represents only approximately 0.1% of transplantations recorded by the ISHLT [3] (Table 1). Lung transplantation is unlikely to be curative but can achieve a 5-year survival rate of 39%, which is similar to that for other end-stage pulmo-nary diseases [33].

Upper Lobe FibrosisUpper lobe fibrosis is uncommon, reported to occur 18–72

months (average, 42 months) after lung transplantation [35] (Fig. 14). The exact pathogenesis is unknown but is hy-pothesized to be a rare manifestation of chronic rejection. Pathologic assessment may show nonspecific inflammation and fibrosis.

High-resolution CT findings include interlobular septal thickening, gradual development of coarse reticular opaci-ties, and mild peripheral ground-glass opacities. The pro-gression of established fibrosis may occur with traction bronchiectasis, honeycombing, architectural distortion, and volume loss. The upper lobes are initially involved, with the subsequent development of smaller volumes of fibrosis in the superior segments of the lower lobes [35]. The basal segments are minimally involved.

Patients develop progressive dyspnea. Pulmonary function tests may show a mixed obstructive and restrictive pattern.

Complications After Transbronchial BiopsySolid and cavitary nodules (2–15 mm) with surrounding

ground-glass attenuation may be identified on CT up to 1 month after transbronchial biopsy [36] (Fig. 15). The ground-glass attenuation represents hemorrhage secondary to biopsy. The nodules may not be immediately evident on chest radiographs. The temporal relationship to the biopsy and the location at known biopsy sites should prevent con-fusion with infection or rejection.

SummaryRadiology plays a pivotal role in the diagnosis and man-

agement of complications of lung transplantation. Radiol-ogists should be familiar with the radiologic appearances of common surgical techniques as well as those of complica-tions of lung transplantation. Because the radiologic pat-tern of disease may be nonspecific, it is critical to know the time course from lung transplantation and relevant postop-erative history in order to generate a clinically useful and relevant radiologic opinion.

References1. Toronto Lung Transplant Group. Unilateral lung transplantation for pulmonary

fibrosis. N Engl J Med 1986; 314:1140–1145

A

Fig. 15—After transbronchial lung biopsy, nodules are confined to one lung because surveillance transbronchial biopsies are only performed from one lung, usually the right, at our institution.A, 42-year-old man who underwent surveillance bronchoscopy and transbronchial biopsy 7 days before surveillance CT, which showed cavitary nodules (arrow-heads) surrounded by ground-glass attenuation.B, 39-year-old man who underwent surveillance transbronchial biopsy 3 days before surveillance CT, which showed solid nodules (arrows) surrounded by ground-glass attenuation.

B

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2. de Perrot M, Chaparro C, McRae K, et al. Twenty-year experience of lung transplantation at a single center: influence of recipient diagnosis on long-term survival. J Thorac Cardiovasc Surg 2004; 127:1493–1501

3. Trulock EP, Christie JD, Edwards LB, et al. Registry of the International Soci-ety for Heart and Lung Transplantation: twenty-fourth official adult lung and heart-lung transplantation report—2007. J Heart Lung Transplant 2007; 26:782–795

4. Alvarez A, Algar J, Santos F, et al. Airway complications after lung transplan-tation: a review of 151 anastomoses. Eur J Cardiothorac Surg 2001; 19:381–387

5. Lima O, Goldberg M, Peters WJ, Ayabe H, Townsend E, Cooper JD. Bronchial omentopexy in canine lung transplantation. J Thorac Cardiovasc Surg 1982; 83:418–421

6. Kshettry VR, Kroshus TJ, Hertz MI, Hunter DW, Shumway SJ, Bolman RM 3rd. Early and late airway complications: incidence and management. Ann Thorac Surg 1997; 63:1576–1583

7. McAdams HP, Murray JG, Erasmus JJ, Goodman PC, Tapson VF, Davis RD. Telescoping bronchial anastomosis for unilateral or bilateral sequential lung transplantation: CT appearance. Radiology 1997; 203:202–206

8. Erasmus JJ, McAdams HP, Tapson VF, Murray JG, Davis RD. Radiologic is-sues in lung transplantation for end-stage pulmonary disease. AJR 1997; 169:69–78

9. Van De Wauwer C, Van Raemdonck D, Verleden GM, et al. Risk factors for airway complications within the first year after lung transplantation. Eur J Car-diothorac Surg 2007; 31:703–710

10. Date H, Trulock EP, Arcidi JM, Sundaresan S, Cooper JD, Patterson GA. Im-proved airway healing after lung transplantation: an analysis of 348 bronchial anastomoses. J Thorac Cardiovasc Surg 1995; 110:1424–1433

11. Murray JG, McAdams HP, Erasmus JJ, et al. Complications of lung transplan-tation: radiologic findings. AJR 1996; 166:1405–1411

12. Collins J, Kuhlman JE, Love RB. Acute, life-threatening complications of lung transplantation. RadioGraphics 1998; 18:21–43

13. Herman SJ, Weisbrod GL, Weisbrod L, Patterson GA, Maurer JR. Chest radio-graphic findings after bilateral lung transplantation. AJR 1989; 153:1181–1185

14. Semenkovich JW, Glazer HS, Anderson DC, Arcidi JM Jr, Cooper JD, Patter-son GA. Bronchial dehiscence in lung transplantation: CT evaluation. Radiolo-gy 1995; 194:205–208

15. Quint LE, Whyte RI, Kazerooni EA, et al. Stenosis of the central airways: evaluation by using helical CT with multiplanar reconstructions. Radiology 1995; 194:871–877

16. Clark SC, Levine AJ, Hasan A, Hilton CJ, Forty J, Dark JH. Vascular compli-cations of lung transplantation. Ann Thorac Surg 1996; 61:1079–1082

17. Frost AE. Donor criteria and evaluation. Clin Chest Med 1997; 18:231–237

18. Ward S, Müller NL. Pulmonary complications following lung transplantation. Clin Radiol 2000; 55:332–339

19. Collins J, Love RB. Pulmonary torsion: complication of lung transplantation.

Clin Pulm Med 1996; 3:297–298

20. Ferrer J, Roldan J, Roman A, et al. Acute and chronic pleural complications in lung transplantation. J Heart Lung Transplant 2003; 22:1217–1225

21. Herridge MS, de Hoyos AL, Chaparro C, Winton TL, Kesten S, Maurer JR. Pleural complications in lung transplant recipients. J Thorac Cardiovasc Surg 1995; 110:22–26

22. Kundu S, Herman SJ, Winton TL. Reperfusion edema after lung transplanta-tion: radiographic manifestations. Radiology 1998; 206:75–80

23. Garg K, Zamora MR, Tuder R, et al. Lung transplantation: indications, donor and recipient selection, and imaging of complications. RadioGraphics 1996; 16:355–367

24. Gotway MB, Dawn SK, Sellami D, et al. Acute rejection following lung trans-plantation: limitations in accuracy of thin-section CT for diagnosis. Radiology 2001; 221:207–212

25. Bergin CJ, Castellino RA, Blank N, Berry GJ, Sibley RK, Starnes VA. Acute lung rejection after heart–lung transplantation: correlation of findings on chest radiographs with lung biopsy results. AJR 1990; 155:23–27

26. Loubeyre P, Revel D, Delignette A, Loire R, Mornex JF. High-resolution com-puted tomographic findings associated with histologically diagnosed acute lung rejection in heart–lung transplant recipients. Chest 1995; 107:132–138

27. Collins J, Müller NL, Kazerooni EA, Paciocco G. CT findings of pneumonia after lung transplantation. AJR 2000; 175:811–818

28. Reams BD, McAdams HP, Howell DN, Stelle MP, Davis RD, Palmer SM. Posttransplant lymphoproliferative disorder: incidence, presentation and re-sponse to treatment in lung transplant recipients. Chest 2003; 124:1242–1249

29. Nicod LP. Mechanisms of airway obliteration after lung transplantation. Proc Am Thorac Soc 2006; 3:444–449

30. Chamberlain D, Maurer J, Chaparro C, Idolor L. Evaluation of transbronchial lung biopsy specimens in the diagnosis of bronchiolitis obliterans after lung transplantation. J Heart Lung Transplant 1994; 13:963–971

31. Morrish WF, Herman SJ, Weisbrod GL, Chamberlain DW. Bronchiolitis oblit-erans after lung transplantation: findings at chest radiography and high resolu-tion CT. The Toronto Lung Transplant Group. Radiology 1991; 179:487–490

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Imaging of Lung Transplantation: Self-Assessment ModuleYuen Li Ng1, 2, Narinder Paul3, Demetris Patsios3, Anna Walsham4, Tae-Bong Chung3, Shaf Keshavjee5, Gordon Weisbrod3

Keywords: lung transplantation

DOI:10.2214/AJR.07.7130

Received November 29, 2007; accepted without revision February 19, 2008.1CT Unit, Jubilee Wing, Department of Clinical Radiology, Leeds General Infirmary, Leeds LS1 3EX, West Yorkshire, United Kingdom. 2Present address: Department of Diagnostic Radiology, Singapore General Hospital, Outram Rd., Singapore 169608. Address correspondence to Y. L. Ng ([email protected]).3Joint Department of Medical Imaging, Thoracic Division, University Health Network and Mount Sinai Hospital, Toronto General Hospital, Toronto, ON, Canada.4Department of Clinical Radiology, Hope Hospital, Manchester, United Kingdom.5Division of Thoracic Surgery and Toronto Lung Transplant Program, Toronto General Hospital, Toronto, ON, Canada.


ABSTRACT

ObjectiveThe educational objectives of this continuing medical

education activity are for the reader to exercise, self-assess, and improve skills in diagnostic radiology with regard to imaging of lung transplantation and to improve familiarity with the complications of lung transplantation.

ConclusionThe articles in this activity review the imaging and com-

plications of lung transplantation and discuss the role of imaging in the assessment of complications from lung transplantation.

INTRODUCTION This self-assessment module on imaging of lung transplan-

tation has an educational component and a self-assessment component. The educational component consists of one re-quired article that the participant should read. The self-as-sessment component consists of 10 multiple-choice questions with solutions. All of these materials are available on the ARRS Website (www.arrs.org). To claim CME and SAM credit, each participant must first order the CME activity, then enter his or her responses to the questions online.

EDUCATIONAL OBJECTIVESBy completing this educational activity, the participant will:

A. Exercise, self-assess, and improve his or her understand-ing of the imaging of lung transplantation.

B. Exercise, self-assess, and improve his or her understand-ing of the complications of lung transplantation.

REQUIRED READING1. Ng YL, Paul N, Patsios D, et al. Imaging of lung trans-

plantation: review. AJR 2009; 192[suppl]:

INSTRUCTIONS1. Complete the educational and self-assessment compo-

nents included in this issue. 2. Visit www.arrs.org and log in. 3. Select Publications/Journals/SAM Articles from the left-

hand menu bar. 4. Order the online SAM as directed. (The SAM must be

ordered to be accessed even though the activity is free to ARRS members.)

5. The SAM can be accessed at www.arrs.org/My Educa-tion/My Online Products, but you must be logged in to access this personalized page.

6. Answer the questions online to obtain SAM credit.

1.5 CME1.0 SAM

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QUESTION 1

Concerning early complications of lung transplantation, which of the following is TRUE?

A. Bronchial dehiscence is usually diagnosed on chest radiography.

B. Reimplantation response is a form of noncardio-genic pulmonary edema and occurs in more than 95% of lung transplantation patients.

C. CT features of acute rejection, such as ground-glass opacities, interlobular septal thickening, nodules, and consolidation, are accurate in the diagnosis and assessment of severity of acute rejection.

D. Acute rejection responds poorly to corticosteroids.

QUESTION 2

Concerning late complications of lung transplantation, which of the following statements is FALSE?

A. Obliterative bronchiolitis usually develops 6–18 months after transplantation and is associated with previous multiple episodes of acute rejection and cytomegalovirus (CMV) pneumonia.

B. Obliterative bronchiolitis is a histologic diagnosis affecting the small airways and is reliably excluded by negative transbronchial biopsy.

C. Upperlobefibrosisishypothesizedtobeararemanifestation of chronic rejection in lung trans-plantation patients.

D. Posttransplantation lymphoproliferative disorder occurs more commonly in patients with lung transplants than in patients with other solid organ transplants.

QUESTION 3

Which of the following statements regarding infection after lung transplantation is FALSE?

A. Bacterialinfectionsusuallyoccurinthefirstmonthafter transplantation.

B. Most common bacterial infections are due to gram-negative bacilli such as Klebsiella organisms and Pseudomonas aeruginosa.

C. Aspergillosis is more prevalent in lung transplanta-tion patients than in other immunocompromised patients.

D. Pulmonary nodules on CT with a surrounding halo ofgroundglassarespecificforinvasiveaspergillosisin lung transplantation patients.

QUESTION 4

Which of the following statements is TRUE regarding CMV infection after lung transplantation?

A. CMV infection is the most common cause of pneumonia.

B. CMV infection is the most common opportunistic infection.

C. Primary CMV infection occurs in seropositive recipients who receive a graft from a seropositive donor.

D. Secondary CMV infection develops from re-activation of a latent virus or from infection with a different CMV strain and is usually more serious than primary infection.

E. Posttransplantation lymphoproliferative disorder is thought to be secondary to B-lymphocyte pro-liferation in response to CMV infection.

QUESTION 5

Which of the following features is LEAST commonly seen on CT in obliterative bronchiolitis after lung transplantation?

A. Bronchial wall thickening and dilatation.B. Nodules.C. Pleural effusion.D. Mosaic attenuation.E. Air trapping.

QUESTION 6

Concerning pulmonary parenchymal complications after lung transplantation, which of the following is LEAST LIKELY to manifest as pulmonary nodules?

A. Invasive pulmonary aspergillosis.B. Reimplantation response.C. Bronchial carcinoma.D. Hematoma after transbronchial biopsy.E. Posttransplantation lymphoproliferative disorder.



sertion and assessing position of stents [5]. Option C is not the best response. CT features of acute rejection are non-specific (i.e., ground-glass opacities, interlobular septal thickening, nodules, and consolidation), and CT is of limit-ed accuracy in the diagnosis or grading of severity of acute rejection [6]. Transbronchial biopsy is often performed to confirm the diagnosis and to exclude infection [7]. Pathol-ogy showed perivascular lymphocytic infiltrates, which may progress to extend into the alveolar septa and alveoli. Acute rejection is histologically graded on a scale of 0–4 on the basis of the severity of the reaction. Option D is not the best response. The most useful diagnostic feature of acute rejection is the dramatic clinical and radiographic response to corticosteroids and increased immunosuppression [7, 8].

Solution to Question 1Option B is the best response. Reimplantation response

occurs in more than 95% of lung transplantation patients [1]. The pathogenesis is probably multifactorial: increased vascular permeability due to ischemia and subsequent re-perfusion, lymphatic interruption, lung denervation, de-creased surfactant production, and surgical trauma [2]. Op-tion A is not the best response. Airway complications are usually diagnosed at bronchoscopy. Chest radiographs are unreliable in the diagnosis of airway complications [3]. CT is useful in the diagnosis of bronchial dehiscence, showing extraluminal gas and focal bronchial wall defects [4]. CT can also show bronchial stenoses and is particularly valu-able in assessing the length of stenoses to plan for stent in-

QUESTION 7

Which of the following statements concerning patients after lung transplantation is FALSE?

A. Acute rejection is the most common cause of mortalityduringthefirst6monthsafterlung transplantation.

B. Obliterative bronchiolitis is the most common cause of mortality in lung transplantation patients beyond 6 months after transplantation.

C. Empyema is the only pleural complication associated with increased mortality and should be excluded in a new or enlarging pleural effusion after lung transplantation.

D. The overall reported 5-year survival rate for lung transplantation patients is approximately 50%.

QUESTION 8

Which of the following statements concerning airway complications after lung transplantation is FALSE?

A. Airway anastomotic complications was one of the major obstacles to success in the early years of lung transplantation but is now rarely encountered (< 1% of lung transplantation patients).

B. Bronchial dehiscence is the most common airway complication in the early postoperative period, typically occurring 2–4 weeks after transplantation.

C. CT occasionally shows a focal bronchial wall defect that is pathognomonic of bronchial dehiscence.

D. Bronchial stricture formation occurs later in the postoperative period, an average of 3 months after transplantation.

QUESTION 9

Which of the following statements is TRUE regarding pleural complications after lung transplantation?

A. Pneumothorax is a rare complication after lung transplantation.

B. Persistent or enlarging pneumothorax in the presence of thoracostomy drains should prompt further investigations to elucidate the cause of the air leak.

C. Pleural effusions seldom occur in patients after lung transplantation.

D. Pleural effusions are usually self-limiting and resolve within 2 months.

QUESTION 10

The figure above shows a single axial CT image of a 53year old patient on day 2 after bilateral lung transplantation. What is the MOST LIKELY diagnosis?

A. Acute rejection.B. Bacterial infection.C. Fungal infection.D. Reimplantation response.

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Solution to Question 2Option B, which is not true, is the best response. Oblitera-

tive bronchiolitis is a histologic diagnosis affecting the small airways in a patchy distribution; transbronchial biopsy may not be diagnostic, particularly in the early stages [9]. Therefore, this disorder is frequently diagnosed clinically, using the term “bronchiolitis obliterans syndrome,” on the basis of an otherwise unexplained decline in lung function [10]. Option A is a true statement and therefore is not the best response [7]. Option C is not the best response. Upper lobe fibrosis is uncommon, reported to occur 18–72 months after lung transplantation [11]. The exact pathogenesis is unknown but is hypothesized to be a rare manifestation of chronic rejection. Pathology may show nonspecific inflam-mation and fibrosis. Option D is not the best response. Post-transplantation lymphoproliferative disorder (PTLD) is a spectrum of diseases that vary from a histologically benign polyclonal lymphoid proliferation to aggressive high-grade lymphoma [12]. The incidence is approximately 5% (range, 1.8–20%), which is more common than in patients with other solid organ transplants [12, 13]. In contrast to other solid organ transplantation patients, PTLD in lung trans-plantation patients usually manifests as pulmonary nodules or masses [12], and extrapulmonary involvement is less common (e.g., hilar or mediastinal adenopathy, thymic en-largement, pleural effusions, and pericardial masses) [13].

Solution to Question 3Option D is the best response. Pulmonary nodules with a sur-

rounding halo of ground glass (i.e., the CT halo sign) were orig-inally described in patients with angioinvasive pulmonary aspergillosis [14]. Since then, however, this appearance has been recognized in other infections (e.g., candidiasis, cytomegalovi-rus [CMV]), neoplastic disorders (e.g., PTLD, bronchio-loalveolar carcinoma), and inflammatory conditions (e.g., he-matoma after transbronchial biopsy) [15]. Options A and B are not the best responses. Bacterial infections account for at least 50% of all infections [13]. The incidence is highest in the first month, but the possibility of bacterial infection remains throughout the patient’s life. Most common causative organ-isms are gram-negative bacilli such as Klebsiella organisms, Pseudomonas aeruginosa, and Enterobacter cloacae. Gram-posi-tive organisms such as Staphylococcus aureus are also observed [7, 13]. Option C is not the best response. Aspergillosis is more prevalent in lung transplantation patients than in other immunocompromised patients. Locally invasive or disseminat-ed aspergillus infection accounts for 2–33% of infections after lung transplantation and 4–7% of all lung transplantation deaths [16]. Aspergillus can cause indolent pneumonia or ful-minant angioinvasive infection with systemic dissemination.

Solution to Question 4Option B is the best response. CMV is the most common

opportunistic infection after lung transplantation [16]. Op-

tion A is not the best response. CMV is the second most common cause of pneumonia (after bacterial infection) in lung transplantation patients [16]. Options C and D are not the best responses. Primary infection occurs in CMV-sero-negative recipients who receive a graft from a seropositive donor. Infection develops in more than 90% and is serious in 50–60% of cases [16]. Thus, CMV matching between do-nor and recipient is performed whenever possible. Second-ary infection develops from reactivation of a latent virus after immunosuppression or from infection with a different CMV strain. It is usually less serious than a primary infec-tion [7]. Option E is not the best response. PTLD is thought to be secondary to B-lymphocyte proliferation in response to Epstein-Barr virus (EBV) infection [13]. It is more com-monly seen in EBV-seronegative recipients who receive an EBV-seropositive donor lung.

Solution to Question 5Option C is the best response. Pleural effusion is the least

likely of the listed findings to be seen in obliterative bronchioli-tis. CT findings of obliterative bronchiolitis include bronchial dilatation, bronchial wall thickening, nodular and linear opac-ities, air trapping, mosaic attenuation, and peribronchovascu-lar infiltrates that are most marked in the lower lobes [17]. Air trapping is the most frequent feature. However, its presence may be intermittent in patients with obliterative bronchiolitis and is of limited sensitivity for the early diagnosis of oblitera-tive bronchiolitis [18]. Options A, B, D, and E, which are likely findings, are not the best responses.

Solution to Question 6Option B is the best response. Reimplantation response (or

reperfusion edema) is a form of noncardiogenic pulmonary edema. Chest radiography and CT typically show bilateral perihilar and basal air-space opacification [1]. Options A, C, D, and E are not the best responses. Pulmonary nodules after lung transplantation are largely due to infection, PTLD, and malignancy [19]. Chest radiography is a useful screening tool, but CT is more sensitive in detecting and characterizing nod-ules. Bronchoscopy with bronchioalveolar lavage and trans-bronchial biopsy, as well as CT-guided and video-assisted thoracic surgery biopsy, should also be considered. Solid and cavitary nodules with surrounding ground-glass attenuation may be identified on CT up to 1 month after transbronchial biopsy. The ground-glass attenuation represents hemorrhage secondary to biopsy. The temporal relationship to the biopsy and the location at known biopsy sites should prevent confu-sion with infection [20].

Solution to Question 7Option A is the best response. Infection is the most com-

mon cause of mortality during the first 6 months after lung transplantation [21]. Patients have an increased suscepti-bility to infection because of immunosuppression, lung



denervation with loss of the cough reflex, impaired muco-ciliary function, and lymphatic drainage [7, 16]. Option B is not the best response. Chronic rejection or obliterative bron-chiolitis is the most common cause of mortality more than 6 months after lung transplantation [21]. Option C is not best response. Pleural effusions occur in almost all patients but are usually self-limiting and resolve within 2 weeks [2, 22]. Persistent or new effusions suggest a complication such as empyema. A single communicating pleural space com-monly develops after bilateral lung and heart–lung trans-plantations. Therefore, empyema may affect both hemitho-races with potentially disastrous consequences [7, 22–24]. Option D is not the best response as it is a true statement. The reported survival rates from January 1994 to June 2005 were 87% at 3 months, 78% at 1 year, 62% at 3 years, 50% at 5 years, and 26% at 10 years.

Solution to Question 8Option A, which is not true, is the best response. Although

the incidence of airway complications has decreased with improved surgical and donated-organ preservation tech-niques, immunosuppression, and posttransplantation sur-veillance [7, 25, 26], airway complications still cause signifi-cant morbidity and have been estimated to occur in approximately 5–15% of lung transplantation patients [24–28]. Options B and C are not the best responses. Bron-chial dehiscence is the most common airway complication in the early postoperative period, affecting 2–3% of cases [2, 21, 27]. CT typically shows the presence of extraluminal gas and, occasionally, the focal bronchial wall defect that is pathognomonic of this condition [4]. Indirect signs of bron-chial dehiscence include the presence of a new or persistent air leak, pneumothorax, and pneumomediastinum. Option D is not the best response because it is a true statement. Bronchial stricture formation is seen in approximately 10% of patients [26–28].

Solution to Question 9Option B is the best response. Pneumothorax usually re-

solves with the insertion of thoracostomy drains [7, 23]. New, persistent, or enlarging pneumothoraces should prompt further investigation to elucidate the cause of the air leak. Option A is not the best response. Pneumothorax is the most common pleural complication after lung trans-plantation [7, 23]. Bilateral lung and heart–lung transplan-tations frequently result in a single communicating pleural space. Therefore, pneumothoraces are often bilateral [7]. Options C and D are not the best responses. Pleural effu-sions develop in almost all transplantation patients because of increased capillary permeability and impaired lymphatic clearance of the transplanted lung [2, 22]. They are usually self-limiting and resolve within 2 weeks. Persistent or de-layed effusions suggest complicated effusions such as empy-ema, organized hematoma, rejection, and PTLD.

Solution to Question 10Option D is the best response. The CT image shows bilat-

eral ground-glass opacities, air-space consolidation, and interlobular septal thickening. At day 2 after lung trans-plantation, reimplantation response is the most likely diag-nosis. Reimplantation response frequently begins by day 1, is always present by day 3, peaks by day 4 or 5, and resolves by day 10 [7, 13]. In clinical practice, it is usually diagnosed after exclusion of left ventricular failure, fluid overload, transplant rejection, and infection [1, 8]. Options A, B, and C are not the best responses. The radiologic features of acute rejection and pneumonia may be similar to those of reimplantation response [16, 29]. However, acute rejection and pneumonia tend to occur later than reimplantation re-sponse after lung transplantation. Acute rejection usually occurs within the first 3 weeks, typically between days 5 and 10 [7]. Bacterial pneumonia tends to predominate in the first month after lung transplantation, and fungal pneu-monia usually occurs between 10 and 60 days after trans-plantation [16].

References 1. Kundu S, Herman SJ, Winton TL. Reperfusion edema after lung transplanta-

tion: radiographic manifestations. Radiology 1998; 206:75–80

2. Collins J, Kuhlman JE, Love RB. Acute, life-threatening complications of lung transplantation. RadioGraphics 1998; 18:21–43

3. Herman SJ, Weisbrod GL, Weisbrod L, Patterson GA, Maurer JR. Chest radio-graphic findings after bilateral lung transplantation. AJR 1989; 153:1181–1185

4. Semenkovich JW, Glazer HS, Anderson DC, Arcidi JM Jr, Cooper JD, Pat-terson GA. Bronchial dehiscence in lung transplantation: CT evaluation. Radi-ology 1995; 194:205–208

5. Quint LE, Whyte RI, Kazerooni EA, et al. Stenosis of the central airways: evaluation by using helical CT with multiplanar reconstructions. Radiology 1995; 194:871–877

6. Gotway MB, Dawn SK, Sellami D, et al. Acute rejection following lung trans-plantation: limitations in accuracy of thin-section CT for diagnosis. Radiology 2001; 221:207–212

7. Erasmus JJ, McAdams HP, Tapson VF, Murray JG, Davis RD. Radiologic is-sues in lung transplantation for end-stage pulmonary disease. AJR 1997; 169:69–78

8. Garg K, Zamora MR, Tuder R, et al. Lung transplantation: indications, donor and recipient selection, and imaging of complications. RadioGraphics 1996; 16:355–367

9. Chamberlain D, Maurer J, Chaparro C, Idolor L. Evaluation of transbronchial lung biopsy specimens in the diagnosis of bronchiolitis obliterans after lung transplantation. J Heart Lung Transplant 1994; 13:963–971

10. Nicod LP. Mechanisms of airway obliteration after lung transplantation. Proc Am Thorac Soc 2006; 3:444–449

11. Konen E, Weisbrod GL, Pakhale S, et al. Fibrosis of the upper lobes: a newly identified late-onset complication after lung transplantation? AJR 2003; 181:1539–1543

12. Reams BD, McAdams HP, Howell DN, Stelle MP, Davis RD, Palmer SM. Posttransplant lymphoproliferative disorder: incidence, presentation and re-sponse to treatment in lung transplant recipients. Chest 2003; 124:1242–1249

13. Murray JG, McAdams HP, Erasmus JJ, et al. Complications of lung transplan-tation: radiologic findings. AJR 1996; 166:1405–1411

14. Kuhlman JE, Fishman EK, Siegelman SS. Invasive pulmonary aspergillosis in acute leukemia: characteristic findings on CT, the CT halo sign, and the role of CT in early diagnosis. Radiology 1985; 157:611–614

15. Lee YR, Choi YW, Lee KJ, Jeon SC, Park CK, Heo JN. CT halo sign: the

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spectrum of pulmonary diseases. Br J Radiol 2005; 78:862–865

16. Collins J, Muller NL, Kazerooni EA, Paciocco G. CT findings of pneumonia after lung transplantation. AJR 2000; 175:811–818

17. Morrish WF, Herman SJ, Weisbrod GL, Chamberlain DW. Bronchiolitis oblit-erans after lung transplantation: findings at chest radiography and high resolu-tion CT. The Toronto Lung Transplant Group. Radiology 1991; 179:487–490

18. Konen E, Gutierrez C, Chaparro C, et al. Bronchiolitis obliterans syndrome in lung transplant recipients: can thin-section CT findings predict disease before its clinical appearance? Radiology 2004; 231:467–473

19. Lee P, Minai OA, Mehta AC, DeCamp MM, Murthy S. Pulmonary nodules in lung transplant recipients. Chest 2004; 125:165–172

20. Kazerooni EA, Cascade PN, Gross BH. Transplanted lungs: nodules following transbronchial biopsy. Radiology 1995; 194:209–212

21. de Perrot M, Chaparro C, McRae K, et al. Twenty-year experience of lung transplantation at a single center: influence of recipient diagnosis on long-term survival. J Thorac Cardiovasc Surg 2004; 127:1493–1501

22. Ferrer J, Roldan J, Roman A, et al. Acute and chronic pleural complications in lung transplantation. J Heart Lung Transplant 2003; 22:1217–1225

23. Herridge MS, de Hoyos AL, Chaparro C, Winton TL, Kesten S, Maurer JR.

Pleural complications in lung transplant recipients. J Thorac Cardiovasc Surg 1995; 110:22–26

24. Trulock EP, Christie JD, Edwards LB, et al. Registry of the International Society for Heart and Lung Transplantation: twenty-fourth official adult lung and heart–lung transplantation report—2007. J Heart Lung Transplant 2007; 26:782–795

25. Alvarez A, Algar J, Santos F, et al. Airway complications after lung transplanta-tion: a review of 151 anastomoses. Eur J Cardiothorac Surg 2001; 19:381–387

26. Date H, Trulock EP, Arcidi JM, Sundaresan S, Cooper JD, Patterson GA. Im-proved airway healing after lung transplantation: an analysis of 348 bronchial anastomoses. J Thorac Cardiovasc Surg 1995; 110:1424–1433

27. Kshettry VR, Kroshus TJ, Hertz MI, Hunter DW, Shumway SJ, Bolman RM 3rd. Early and late airway complications: incidence and management. Ann Thorac Surg 1997; 63:1576–1583

28. Van De Wauwer C, Van Raemdonck D, Verleden GM, et al. Risk factors for airway complications within the first year after lung transplantation. Eur J Cardiothorac Surg 2007; 31:703–710

29. Bergin CJ, Castellino RA, Blank N, Berry GJ, Sibley RK, Starnes VA. Acute lung rejection after heart–lung transplantation: correlation of findings on chest radiographs with lung biopsy results. AJR 1990; 155:23–27




CT Virtual Endoscopy in the Evaluation of Large Airway Disease: ReviewBradley P. Thomas1, Megan K. Strother, Edwin F. Donnelly, John A. Worrell

Keywords: airway disease, choanal atresia, CT, CT virtual endoscopy, infiltrative airway disease, transbronchial biopsy

DOI:10.2214/AJR.07.7077

Received February 5, 2008; accepted after revision June 2, 2008.1All authors: Department of Radiology and Radiological Sciences, Vanderbilt University Medical Center, CCC-1121, MCN, 1161 21st Ave. S, Nashville, TN 37232-2675. Address correspondence to B. P. Thomas ([email protected]).


ObjectiveThe purpose of this article is to illustrate the usefulness

and limitations of CT virtual endoscopy in the evaluation of large airway disease.

ConclusionCT virtual endoscopy is a postprocessing tool that is easy

to perform and that can aid in depicting disorders of the large airways without additional radiation or cost other than added time in postprocessing. The benefits of this technique include noninvasive diagnostic surveillance and preoperative planning.

IntroductionCT virtual endoscopy has been used to evaluate pathologic

processes of the nasopharynx, larynx, and tracheobronchial tree [1–5]. Findings are generally made first on the CT source images. The stunning CT virtual endoscopic images subse-quently generated allow pulmonologists and otolaryngolo-gists the anatomic perspectives of the large airway that they are clinically accustomed to viewing. Effective clinical con-sultation requires the practicing radiologist to be familiar with the technique of generating these images, as well as the anatomy and pathologic conditions shown.

CT Virtual Endoscopy TechniqueUnlike virtual colonoscopy, no preprocedural patient

preparation is needed to evaluate the large airways. CT vir-tual endoscopy applications are performed retrospectively to aid in the depiction of data detected on routine image interpretation that may be useful to referring physicians. The high contrast of an air-filled lumen renders 3D and 4D imaging that closely resembles the conventional endoscopic correlate. All CT virtual endoscopy review was performed after approval of the institutional review board, using diag-nostic neck and chest CT scans at our institution. All CT examinations were performed on either the 64-MDCT Bril-liance CT scanner or the 16-MDCT MX8000IDT CT scan-

ner (both Philips Healthcare) using routine departmental protocols (Table 1). With the 64-MDCT scanner, isotropic data are acquired routinely on all chest and neck CT scans. Because dose efficiency is quite high with the 64-MDCT scanner, there is no significant radiation cost to the patient for isotropy. Some additional radiation dose occurs when acquiring isotropic data with the 16-MDCT scanner. At our institution, isotropic data are routinely acquired on neck CT examinations to allow high-quality multiplanar refor-mations. Although no preprocedure preparation is required, imaging of the proximal airways can be optimized for lumi-nal distention with maximum aeration using either the modified Valsalva or the phonation technique [6].

Postprocessing was performed with the virtual endoscopy application. Using CT virtual endoscopy application soft-ware, preset tissue algorithms (e.g., trachea) change the color scheme and set thresholds that define the tissue–air interface. Once the data are loaded into the endoscopy application, the cursor can be moved into the airway lumen, and the observ-er’s view is directed as desired using the swivel tool to provide the best images of the desired region. It is helpful to orient the image to correspond with a conventional endoscopic view. For example, nasal endoscopy is performed in a face-to-face doctor–patient orientation. This is in contrast to bronchos-copy, in which the bronchoscopist is usually positioned be-hind the patient, having the same right–left orientation. La-beling the CT virtual endoscopic images may be necessary for clarification. Postprocessing requires approximately 10 addi-tional minutes per examination.

Virtual Nasopharyngoscopy and Laryngoscopy

Choanal AtresiaCT virtual endoscopy of the normal nasopharynx from a

posterior viewpoint provides a look at the eustachian tube openings in reference to the choanae and nasopharyngeal walls, an area difficult to appreciate with conventional CT

Thomas et al.


[1] (Fig. 1A). This is compared to a 4-year-old girl in whom the right posterior nasal cavity is blocked, consistent with choanal atresia (Figs. 1B and 1C). Note the abnormally thickened vomer in choanal atresia, a finding important in diagnosis and preoperative planning [7].

EpiglottitisCompare the normal epiglottis (Fig. 2A) with that of an

immunocompromised patient who presented to the emer-gency department with a markedly thickened epiglottis and symptoms consistent with acute epiglottitis (Figs. 2B

A

C

Fig. 1—4-year-old girl with bony right-sided choanal atresia.A, Normal posterior nasopharynx CT virtual endoscopic view with roof of naso-pharynx above and soft palate (sp) below showing choanae (curved arrow), turbinates (t), and eustachian tube opening (straight arrow).B and C, CT virtual endoscopy (B) and axial CT (C) images show bony obstruc-tion (arrow, B) and characteristically thickened vomer (asterisk, B). sp = soft palate, t = turbinates.

B

TABLE 1: Protocols Used in CT Virtual Endoscopy Examples

Scanner kVp mAs Collimation (mm) Pitch Rotation Time (s) Matrix Field of View (mm)

64-MDCT, Brilliance

Neck 120 300 64 × 0.625 0.891 0.75 512 250

Chest 120 250 32 × 1.25 0.906 0.75 512 400

16-MDCT, MX8000IDT

Neck 120 300 16 × 0.75 0.9 0.75 512 250

Chest 140 150 16 × 0.75 0.9 0.75 512 400

Note—Both scanners are by Philips Healthcare.


CT Virtual Endoscopy of Airway Disease

Reinke’s edema is a chronic laryngeal disease found almost exclusively in smokers that is difficult to diagnose with imag-ing alone. Imaging of a 46-year-old woman with a long his-tory of smoking and hoarseness who presented with increas-ingly labored breathing is shown (Fig. 3). CT virtual endoscopy depicts diffuse vocal cord edema with a superimposed poly-poid area of swelling (Fig. 3A). Both true polyps and Reinke’s edema can cause acoustic dysfunction, but the latter is much more likely to cause airway compromise [9]. When glottic ob-struction is present, we have found it difficult to delineate la-ryngeal structures with CT virtual endoscopy (Figs. 2B and 3A). However, laryngeal airway distension techniques may help when evaluating known laryngeal disease [6].

and 2C). CT virtual endoscopy can provide a familiar view to the endoscopist for planning subsequent intervention, which is usually required when the airway is compromised by more than 50% [8].

Vocal Cord LesionsWhen imaging the glottis, evaluation of submucosal extent

of disease is the mainstay of the CT examination. However, CT virtual endoscopy can direct biopsy planning of cord le-sions. With CT virtual endoscopy, the 3D location of polypoid lesions is easier to appreciate. True polyps most often occur along the anterior third of the vocal cord, whereas polypoid corditis, a form of Reinke’s edema, is usually more diffuse.

A

C

Fig. 2—25-year-old man with acute epiglottitis.A, Normal virtual laryngoscopy shows epiglottis (thick arrow), vallecula (v), py-riform sinus (ps), aryepiglottic fold (long thin arrow), arytenoid prominence (short thin arrow), and glottis (asterisk).B and C, Virtual laryngoscopy image (B) and contrast-enhanced CT image (C) show severely edematous epiglottis (thick arrow) and arytenoids (thin arrows).

B

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Virtual TracheoscopyRadiologists should be able to recognize the normal tra-

cheal architecture and anatomic variants. In particular, normal structures such as the transverse aorta can indent the large airways and need not be confused with extrinsic lesions when viewed endoscopically. Note how CT virtual endoscopy nicely shows the posterolateral location of a tra-cheal bronchus from an endoluminal perspective (Fig. 4). CT virtual endoscopy of the trachea is a useful postprocess-ing tool because views of disorders can closely resemble those of conventional endoscopy, making this a much ap-preciated extra step from the endoscopist’s perspective.

Non–Small Cell Lung CancerBiopsy planning in the workup of a lung mass hinges on

lesion location and size. A decision must be made whether to perform percutaneous, open, or transbronchial biopsy. Vir-tual tracheobronchoscopy can guide this decision-making algorithm by assessing extrinsic mass effect. If a peribron-chial lesion is exerting mass effect, transbronchial biopsy may be performed successfully. In this example, we studied a 64-year-old man with vocal cord paralysis due to mediastinal invasion of non–small cell lung cancer. In conjunction with the axial CT appearance, virtual tracheoscopy can further evaluate true vocal cord paralysis (Figs. 5A and 5B) second-

A

C

Fig. 3—46-year-old woman with Reinke’s edema.A, Virtual laryngoscopy image shows edematous true vocal cords (asterisks) and polypoid mass emanating from mid and posterior left true cord (arrow).B, Conventional endoscopic view in same patient, now undergoing intubation, shows lobulated lesion.C, Axial contrast-enhanced CT image shows polypoid mass (arrow) and lack of deep invasion.

B



ary to recurrent laryngeal nerve involvement by a stage T4 mediastinal mass (Figs. 5C and 5D). Note the obscuring of the right bronchial orifice as compared with a more normal-caliber distal trachea (Fig. 4). Virtual tracheobronchoscopy has promise for transluminal biopsy planning [5].

Postintubation Tracheal StenosisEndotracheal intubation is the most common cause of ac-

quired tracheal stenosis, which may follow prolonged tra-cheal balloon inflation. With the implementation of low-pressure cuffs, the incidence has been reduced to less than 1% [10]. Presented here is one such example in a 14-year-old boy who sustained burns and underwent intubation for less than a week, 1 month before this CT examination (Fig. 6). Focal stenoses, usually less than 2 cm in length, can be diffi-cult to appreciate on conventional radiographs [10]. Like-wise, focal stenoses may be overlooked on routine axial CT images because the orientation of the stenosis is in the plane of image acquisition. Tracheal stenoses are much better ap-preciated with coronal reformations and CT virtual endos-copy, which is a view that is helpful to the surgeon [5].

Recurrent Respiratory PapillomatosisJuvenile-onset recurrent respiratory papillomatosis usu-

ally begins in the larynx, specifically along the anterior third of the vocal cords [11], but can spread anywhere in the tracheobronchial tree. Involvement of the lower air-ways and lungs occurs in 5–28.8% of patients and carries a more serious prognosis [11]. Managing this disease may re-quire countless bronchoscopies and laser treatment of dom-inant papillomas in effort to prevent airway compromise and malignant degeneration [10]. Between treatments, CT virtual endoscopy can provide surveillance, particularly in the evaluation of larger lesions. Although abundant infor-mation regarding texture of the mucosa and lesions can be obtained with fiberoptic imaging (Figs. 7B and 7D), the relative size of the lesions is nicely depicted on the CT vir-

Fig. 4—Normal anatomic variants. Virtual tracheoscopy of distal trachea shows cartilaginous rings (short thin arrow), posterior tracheal membrane (asterisk), normal indentation of transverse aorta (thick arrow), and orifice of true tracheal bronchus supplying right upper lobe (long thin arrow).

AFig. 5—64-year-old man with non–small cell lung cancer.A, Virtual laryngoscopic image of open glottis shows anterior commissure (thick arrow), laryngeal ventricle (thin arrow), and medialization of right true vocal cord (asterisk).B, Axial PET/CT fusion image confirms hypometabolism on right (asterisk) compared with normal left laryngeal uptake.

(Fig. 5 continues on next page)

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tual endoscopic images (Figs. 7A and 7C). This noninvasive examination can be of value to patients who often undergo countless endoscopic procedures for surveillance, as in the example of this 23-year-old woman, who was diagnosed at age 2 with this unrelenting disease that has now progressed to involve the lung parenchyma (Fig. 7E).

Tracheobronchial AmyloidosisTracheobronchial amyloidosis is the most common sub-

type of pulmonary amyloidosis. The interstitial and nodu-lar parenchymal patterns occur less frequently [11]. Irregu-lar narrowing and thickening of the tracheobronchial wall are seen routinely on cross-sectional imaging. Here, in a

C

Fig. 5 (continued)—64-year-old man with non–small cell lung cancer.C, Virtual tracheoscopy image with abnormal extrinsic compression of distal right trachea caused by mass lesion (asterisk).D, Axial PET/CT fusion image of chest shows primary tumor.

D

AFig. 6—14-year-old male burn patient with tracheal stenosis.A–C, Virtual tracheoscopy image just above stenosis (arrow, A), correlative conventional endoscopic image (B), and contrast-enhanced coronal CT image (C) show short segment stenosis and dystrophic calcification in submucosa (arrows, C).


B



54-year-old woman who presented initially with shortness of breath and who was treated with bronchoscopically di-rected debulking, CT virtual endoscopy shows the airway lumen and extent of obstruction, which correlate well with the conventional endoscopic view (Figs. 8A–8C). This can be differentiated on axial CT from tracheobronchopathia osteoplastica, which contains calcification in the diseased tracheal wall and characteristically spares the posterior membrane. Wegener’s granulomatosis is another infiltrative disease of the trachea that often involves the subglottic air-way, causing stenosis [10, 12]. CT virtual endoscopy has been shown to increase sensitivity for diagnosing subglottic stenoses in these patients [12].

Treatment of tracheobronchial amyloidosis is difficult and historically has been limited to bronchoscopically di-rected debulking by forceps resection and laser therapy [9]. More recently, external beam radiation therapy (EBRT) has been described as a viable alternative [13]. Volume-ren-dering techniques can provide an overview of the infiltrated tracheal wall, which can potentially help direct EBRT plan-ning (Fig. 8D).

Technical LimitationsAsymmetry is a guide to pathology on endoscopy, but

asymmetries on CT, particularly in the larynx, are most of-ten caused by poor aeration [6]. Because of this, virtual lar-yngoscopy has low specificity in evaluating mucosal lesions of the valleculae, pyriform sinuses, and larynx [2]. There-fore, findings on virtual laryngoscopy should always be evaluated in the context of the original CT data set [2].

The extent of airway compromise may be overestimat-ed on CT virtual endoscopy when the airway is significant-

ly stenosed. The apparent degree of stenosis may vary with different tissue–air threshold values. Lower thresh-old values increase the apparent stenosis, and higher thresholds can produce mucosal gaps [3]. This phenome-non is exemplified in the case of polypoid corditis, with different threshold values yielding different appearances of the pathology (Fig. 9). The degree of glottic narrowing must be approximated with the source CT images. In this case, actual luminal compromise was estimated to be 85% by conventional endoscopy. Therefore, threshold values should be tailored to reflect relative lumen size. This can be performed easily at the workstation by using the mouse to appropriately “window” the threshold value of the 3D image or by manually entering different values into the display options. This also applies to endoluminal lesions. Note that mass lesion size is generally underestimated us-ing CT virtual endoscopy, and measurements should in-stead be made from 2D source CT data [4].

To reiterate, the CT virtual endoscopic images shown in this article were created retrospectively with no changes in routine departmental scanning protocols (Table 1). How-ever, in the evaluation of distal airway disease, advanced protocols such as cardiac gating and submillimeter colli-mation should be considered [14]. Finally, we found no sig-nificant qualitative differences in CT virtual endoscopy images created from the 16-MDCT scanner (Figs. 2 and 8) versus those generated from the 64-MDCT scanner (Figs. 3 and 6).

ConclusionCT virtual endoscopy can be a useful adjunct in the

evaluation of large airway disease. It often elicits a favorable

C

Fig. 6 (continued)—14-year-old male burn patient with tracheal stenosis.A–C, Virtual tracheoscopy image just above stenosis (arrow, A), correlative conventional endoscopic image (B), and contrast-enhanced coronal CT image (C) show short segment stenosis and dystrophic calcification in submucosa (ar-rows, C).

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A

CFig. 7—23-year-old woman with recurrent respiratory papillomatosis that was diagnosed when she was 2 years old.A–D, Virtual tracheoscopy from subglottic and distal tracheal images (A and C) show innumerable plaquelike and exophytic lesions. Compare these with correlative fiberoptic endoscopic images (B and D).


B

D



Fig. 7 (continued)—23-year-old woman with recurrent respiratory papillomato-sis that was diagnosed when she was 2 years old.E, Coronal oblique CT image using lung window setting shows irregularity of airway and associated pulmonary parenchymal cavities.

E

A

Fig. 8—54-year-old woman with tracheobronchial amyloidosis.A and B, CT virtual endoscopic view (A) and correlative conventional endoscopic view (B) show tracheal narrowing and featureless mucosal surface (asterisk, A).


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S10 AJR:192, March 2009

A

CFig. 8 (continued)—54-year-old woman with tracheobronchial amyloidosis.C, Contrast-enhanced axial CT image through region of maximal luminal narrowing shows infiltrative thickening of tracheal wall (arrow).D, Three-dimensional volume-rendered image of trachea shows significant eccentric luminal narrowing (arrow).

Fig. 9—Effect of varying tissue–air interface values in CT virtual endoscopy.A, Preset threshold value of –682 HU exaggerates polypoid lesion and shows artifactual obstruction of glottic opening (arrow).B, Threshold value of –427 HU better depicts the true lumen size (arrow) as compared with axial CT source image.


B

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C

Fig. 9 (continued)—Effect of varying tissue–air interface values in CT virtual endoscopy.C, Threshold value of –100 HU underestimates glottic narrowing (arrow) and produces artificial gaps in tissue surfaces.

response from referring physicians. Recognizing its limi-tations is important, however, to interpret it correctly. In this article, we provide examples to illustrate the useful-ness of CT virtual endoscopy. We also present some tech-nical parameters necessary for the success of virtual en-doscopy. CT virtual endoscopy provides information to clinicians in a format they are most familiar with: endos-copy. Like conventional endoscopy, CT virtual endoscopy can be used for surgical planning, disease monitoring, or patient education.

References1. Rogalla P, Nischwitz A, Gottschalk S, Huitema A, Kaschke O, Hamm B. Vir-

tual endoscopy of the nose and paranasal sinuses. Eur Radiol 1998; 8:946–950

2. Byrne AT, Walshe P, McShane D, Hamilton S. Virtual laryngoscopy: prelimi-nary experience. Eur J Radiol 2005; 56:38–42

3. De Wever W, Vandecaveye V, Lanciotti S, Verschakelen JA. Multidetector CT-generated virtual bronchoscopy: an illustrated review of the potential clinical indications. Eur Respir J 2004; 23:776–782

4. Summers RM, Shaw DJ, Shelhamer JH. CT virtual bronchoscopy of simulated endobronchial lesions: effect of scanning, reconstruction, and display settings and potential pitfalls. AJR 1998; 170:947–950

5. Bauer TL, Steiner KV. Virtual bronchoscopy: clinical applications and limita-tions. Surg Oncol Clin N Am 2007; 16:323–328

6. Henrot P, Blum A, Toussaint B, Troufleau P, Stines J, Roland J. Dynamic ma-neuvers in local staging of head and neck malignancies with current imaging techniques: principles and clinical applications. RadioGraphics 2003; 23:1201–1213

7. Westendorff C, Dammann F, Reinert S, Hoffmann J. Computer-aided surgical treatment of bilateral choanal atresia. J Craniofac Surg 2007; 18:654–660

8. Hafidh MA, Sheahan P, Keogh I, Walsh RM. Acute epiglottitis in adults: a re-cent experience with 10 cases. J Laryngol Otol 2006; 120:310–313

9. Sulica L. Polyps and Reinke’s edema: distinct laryngeal pathologies with dif-ferent potential for glottic airway obstruction. Anesth Analg 2005; 100:1863–1864

10. Prince JS, Duhamel DR, Levin DL, Harrell JH, Friedman PJ. Nonneoplastic lesions of the tracheobronchial wall: radiologic findings with bronchoscopic correlation. RadioGraphics 2002; 22:S215–S230

11. Soldatski IL, Onufrieva EK, Steklov AM, Schepin NV. Tracheal, bronchial, and pulmonary papillomatosis in children. Laryngoscope 2005; 115:1848–1854

12. Summers RM, Aggarwal NR, Sneller MC, et al. CT virtual bronchoscopy of the central airways in patients with Wegener’s granulomatosis. Chest 2002; 121:242–250

13. Neben-Wittich MA, Foote RL, Kalra S. External beam radiation therapy for tracheobronchial amyloidosis. Chest 2007; 132:262–267

14. Khan MF, Herzog C, Ackermann H, et al. Virtual endoscopy of the tracheo-bronchial system: sub-millimeter collimation with the 16-row multidetector scanner. Eur Radiol 2004; 14:1400–1405




CT Virtual Endoscopy in the Evaluation of Large Airway Disease: Self-Assessment ModuleBradley P. Thomas1, Megan K. Strother, Edwin F. Donnelly, John A. Worrell

Keywords: airway disease, choanal atresia, CT virtual endoscopy, infiltrative airway disease, transbronchial biopsy

DOI:10.2214/AJR.07.7129

Received October 7, 2008; accepted without revision October 7, 2008.1All authors: Department of Radiology and Radiological Sciences, Vanderbilt University Medical Center, 1161 21st Ave. S, Nashville, TN 37232-2675. Address correspondence to B. P. Thomas ([email protected]).


ABSTRACT

ObjectiveThe educational objectives of this continuing medical

education activity are for the reader to exercise, self-assess, and improve skills in diagnostic radiology with regard to the imaging evaluation of large airway disease and under-standing the basics of CT virtual endoscopy techniques as well as their limitations.

ConclusionThe articles in this activity review the imaging evalua-

tion of large airway disease and the basics and limitations of CT virtual endoscopy.

INTRODUCTION This self-assessment module on imaging evaluation of

large airway disease has an educational component and a self-assessment component. The educational component consists of three required articles that the participant should read. The self-assessment component consists of 10 multiple-choice questions with solutions. All of these mate-rials are available on the ARRS Website (www.arrs.org). To claim CME and SAM credit, each participant must first or-der the CME activity, then enter his or her responses to the questions online.

EDUCATIONAL OBJECTIVESBy completing this educational activity, the participant will:A. Exercise, self-assess, and improve his or her understand-

ing of the evaluation of large airway disease.B. Understand the basics of CT virtual endoscopy tech-

niques and how the images are produced.

C. Be able to name some disease entities of the large airways that may be further evaluated with CT virtual endoscopy.

D. Learn some limitations of CT virtual endoscopy.

REQUIRED READING1. Thomas BP, Strother MK, Donnelly EF, Worrell JA. CT

virtual endoscopy in the evaluation of large airway dis-ease: review. AJR 2009; 192[suppl]:S00–S00

2. Summers RM, Shaw DJ, Shelhamer JH. CT virtual bron-choscopy of simulated endobronchial lesions: effect of scanning, reconstruction, and display settings and poten-tial pitfalls. AJR 1998; 170:947–950

3. Prince JS, Duhamel DR, Levin DL, Harrell JH, Fried-man PJ. Nonneoplastic lesions of the tracheobronchial wall: radiologic findings with bronchoscopic correlation. RadioGraphics 2002; 22:S215–S230







1.5 CME1.0 SAM

Thomas et al.


Solution to Question 1Option B is the best response. The threshold values in CT virtual

endoscopy refer to definition of tissue–air interface [1]. IV contrast administration has no bearing on CT virtual endoscopy. Option A is not the best response. Endoscopic field of view is a variable that can be chosen by the user at the CT workstation. Option C is not

QUESTION 6

For patients with laryngotracheal disease, CT virtual endoscopy can be useful for which of the following?

A. Planning transbronchial biopsy.B. Measuring endoluminal mass lesions.C. Diagnosing supraglottic malignancy based on

asymmetry.D. Assessing submucosal disease.

QUESTION 7

Which is associated with Reinke’s edema?

A. Easily recognizable on axial CT.B. Acute surgical emergency.C. Chronic airway compromise.D. Direct extension throughout airway.

QUESTION 8

Which is TRUE regarding focal tracheal stenosis?

A. Common after endotracheal intubation.B. High conspicuity on axial CT.C. CT virtual endoscopy may characterize the stenosis.D. Typicallyevaluatedwithfiberopticendoscopy.

QUESTION 9

Which is TRUE regarding recurrent respiratory papillomatosis?

A. Lung involvement has a worse prognosis.B. The age of onset is typically over 50 years.C. Site of origin is usually in the distal airways.D. There is no potential for malignant degeneration.

QUESTION 10

Which of the following is associated with the most common type of pulmonary amyloidosis?A. Interstitialinfiltrates.B. Pulmonary nodules.C. Pleural effusions.D. Tracheobronchial lesions.

QUESTION 1

In CT virtual endoscopy, which of the following is defined by different threshold values?

A. Contrast bolus-tracking time.B. Tissue–air interface.C. Endoscopicfieldofview.D. Postprocessing time.

QUESTION 2

CT virtual endoscopy could be used in the oropharynx and nasopharynx for which of the following?

A. Diagnosis of a mature paratonsillar abscess.B. Assessment of eustachian tube patency.C. Visualizationofeustachiantubeoutflowobstruction.D. Evaluation of dynamic airway collapse.

QUESTION 3

When performed during image acquisition, which of the following may improve the technical quality of CT virtual endoscopy?

A. Rapid breathing.B. Intravenous contrast.C. ModifiedValsalva.D. Swallowing.

QUESTION 4

Which is a disadvantage of CT virtual endoscopy?

A. Increased radiation dose.B. Poor detection of mucosal lesions.C. Inaccurate characterization of stenosis.D. Confusing display of anatomy.

QUESTION 5

Which is TRUE when evaluating endoluminal lesions with CT virtual endoscopy?

A. Measurements do not correlate well with axial CT.B. Lesion texture may be assessed with threshold values.C. Source images for CT virtual endoscopy are

routinely purged.D. Lesion size does not vary with changing threshold

values.

the best response. Postprocessing takes approximately 10 minutes per examination. Option D is not the best response.

Solution to Question 2CT virtual endoscopy of the posterior nasopharynx can

further depict hypertrophy of the adenoid tonsils and the re-



C is the best response. It usually has a chronic course and is not an acute surgical emergency. Option B is not the best response. It may not be seen with conventional CT or CT virtual endoscopy, depending on the degree of true cord edema. Option A is not the best response. Reinke’s edema is a laryngeal disease caused by chronic irritation and does not spread to other parts of the airway. Option D is not the best response.

Solution to Question 8CT virtual endoscopy is useful for evaluating tracheal

stenosis by further depicting the length of the stenosis and assessment of the distal airway [6]. Option C is the best response. Although iatrogenic causes are the reason for focal tracheal stenoses, the incidence after endotrache-al intubation is less than 1% [8]. Option A is not the best response. Tracheal stenosis can easily be overlooked on routine axial CT images because the focal stenosis is in the imaging plane. Option B is not the best response. Fiberop-tic endoscopy is invasive and carries the risk of airway compromise; CT virtual endoscopy is noninvasive. Option D is not the best response.

Solution to Question 9Recurrent respiratory papillomatosis has a worse prog-

nosis when it involves the distal airways [9]. Option A is the best response. Recurrent respiratory papillomatosis usually begins in the larynx, not the distal airways. Op-tion C is not the best response. It is a disease of younger, not older patients. Option B is not the best response. This disease process can cause significant morbidity, including malignant degeneration of papillomas [8]. Option D is not the best response.

Solution to Question 10Tracheobronchial amyloidosis is the most common of the

three types of pulmonary amyloidosis [8]. Option D is the best response. The nodular and interstitial forms are less common. Options A and B are not the best responses. Pleu-ral effusions are not specific for this disease. Option C is not the best response.

References1. De Wever W, Vandecaveye V, Lanciotti S, Verschakelen JA. Multidetector CT-

generated virtual bronchoscopy: an illustrated review of the potential clinical indications. Eur Respir J 2004; 23:776–782

2. Rogalla P, Nischwitz A, Gottschalk S, Huitema A, Kaschke O, Hamm B. Vir-tual endoscopy of the nose and paranasal sinuses. Eur Radiol 1998; 8:946–950

3. Henrot P, Blum A, Toussaint B, Troufleau P, Stines J, Roland J. Dynamic ma-neuvers in local staging of head and neck malignancies with current imaging techniques: principles and clinical applications. RadioGraphics 2003; 23:1201–1213

4. Byrne AT, Walshe P, McShane D, Hamilton S. Virtual laryngoscopy: prelimi-nary experience. Eur J Radiol 2005; 56:38–42

5. Summers RM, Shaw DJ, Shelhamer JH. CT virtual bronchoscopy of simulated endobronchial lesions: effect of scanning, reconstruction, and display settings and potential pitfalls. AJR 1998; 170:947–950

lationship to the eustachian tubes, an area that is difficult to appreciate with conventional CT [2]. Option C is the best re-sponse. The eustachian tube itself cannot be evaluated be-cause it is not normally an air-filled structure. Option B is not the best response. Although some mass effect may be seen with a paratonsillar abscess, it would not be further differenti-ated from paratonsillar phlegmon or other cause of mass ef-fect with CT virtual endoscopy alone. Option A is not the best response. CT virtual endoscopy is usually postprocessed from static CT images and therefore is unable to evaluate dynamic airway collapse. Option D is not the best response.

Solution to Question 3Airway distension maneuvers such as a modified Valsalva

maneuver may help to improve symmetry of the upper air-ways [3]. Option C is the best response. Having the patient swallow or breathe rapidly would introduce motion artifact; Options A and D are not the best responses. Administration of IV contrast material has not been shown to be useful in CT virtual endoscopy. Option B is not the best response.

Solution to Question 4CT virtual endoscopy is not well-suited for the evaluation

of mucosal lesions [4]. Option B is the best response. CT vir-tual endoscopy can help to display complex 3D anatomy and provide useful images from unconventional endoscopic views. Options C and D are not the best responses. There is no added cost or radiation with CT virtual endoscopy. Option A is not the best response.

Solution to Question 5Measurements on CT virtual endoscopy do not correlate

well with conventional axial CT images [5]. Option A is the best response. Lesion size will vary with different tissue–air threshold values, so option D is not the best response. Le-sion texture cannot be readily assessed with CT virtual en-doscopy; option B is not the best response. Furthermore, CT virtual endoscopy should not be interpreted without us-ing the source images. Option C is not the best response.

Solution to Question 6CT virtual endoscopy is useful in transluminal biopsy

planning [6]. Option A is the best response. However, sub-mucosal extent of disease cannot be assessed using stan-dard surface-rendered virtual endoscopic images. Option D is not the best response. Lack of airway distension is a com-mon cause of asymmetry and not a reliable indicator of supraglottic malignancy using CT virtual endoscopy. Op-tion C is not the best response. Measurement of endoluminal mass lesions has been shown to be inaccurate with CT vir-tual endoscopy. Option B is not the best response.

Solution to Question 7Reinke’s edema can have a diffuse, polypoid distribution

that can cause airway compromise [7], which means option

Thomas et al.


6. Bauer TL, Steiner KV. Virtual bronchoscopy: clinical applications and limita-tions. Surg Oncol Clin N Am 2007; 16:323–328

7. Sulica L. Polyps and Reinke’s edema: distinct laryngeal pathologies with differ-ent potential for glottic airway obstruction. Anesth Analg 2005; 100:1863–1864

8. Prince JS, Duhamel DR, Levin DL, Harrell JH, Friedman PJ. Nonneoplastic lesions of the tracheobronchial wall: radiologic findings with bronchoscopic correlation. RadioGraphics 2002; 22[spec no]:S215–S230

9. Soldatski IL, Onufrieva EK, Steklov AM, Schepin NV. Tracheal, bronchial, and pulmonary papillomatosis in children. Laryngoscope 2005; 115:1848–1854




Radiologic Signs in Thoracic Imaging: Case-Based Review and Self-Assessment ModuleMark S. Parker1, Marvin H. Chasen2, Narinder Paul3

Keywords: “head cheese sign,” “hilum convergence sign,” “hilum overlay sign,” “hogs head cheese sign,” “incomplete border sign,” luftsichel sign, thoracic imaging, “walking man sign,” “water bottle sign”

DOI:10.2214/AJR.07.7081

Received March 9, 2008; accepted after revision July 11, 2008.

M. S. Parker is a design consultant for Worldwide Innovations and Technologies, Inc., Overland Park, KS. 1Department of Radiology, Medical College of Virginia Hospitals–VCU Health System, Main Hospital, 3rd Floor, 1250 E Marshall St., PO Box 980615, Richmond, VA 23298-0615. Address correspondence to M. S. Parker ([email protected]).2Department of Diagnostic Radiology, The University of Texas M. D. Anderson Cancer Center, Houston, TX. 3Department of Medical Imaging, Thoracic Imaging, University of Toronto, Toronto, ON, Canada.


ABSTRACT

ObjectiveChest imaging remains one of the most complicated sub-

specialties of diagnostic radiology. The successful interpre-tation of thoracic imaging studies requires the recognition and understanding of the radiologic signs that are charac-teristic of many complex disease processes.

ConclusionThe educational objectives for this case-based self-assess-

ment module are for the participant to exercise, self-assess, and improve his or her understanding of important thorac-ic radiologic signs that are useful in establishing the diagno-sis of particular diseases of the chest.

INTRODUCTIONThis self-assessment module on several radiologic signs

used in thoracic imaging to assist radiologists in establishing a particular diagnosis of pathologic processes affecting the chest has a self-assessment component and an educational component. The self-assessment component consists of six previously unpublished case-based studies with accompany-ing clinical histories and radiologic images. These cases have been selected to illustrate specific radiologic imaging signs. A series of multiple-choice questions follows each case, with so-lutions and a discussion of that particular radiologic sign and its cause. The educational component consists of suggested readings or references that accompany each case that the par-ticipant should review. To claim CME and SAM credit, each participant must log on to the ARRS Website (www.arrs.org) and enter his or her responses to the questions online.

EDUCATIONAL OBJECTIVESBy completing this educational activity, the participant will:

A. Exercise, self assess, and improve his or her understanding of selected radiologic signs useful in establishing a particu-lar diagnosis of pathologic processes affecting the chest.

B. Exercise, self assess, and improve his or her understanding of the underlying cause for these particular imaging signs.

REQUIRED ACTIVITIES1. Six interactive case scenarios presented in this article.

RECOMMENDED READING 1. Woodring JH, Reed JC. Radiographic manifestations

of lobar atelectasis. J Thorac Imaging 1996; 11:109–144 2. Catalano O. The incomplete border sign. Radiology 2002;

225:129–130 3. Chung M, Edinburgh K, Webb E, McCowin M, Webb W.

Mixed infiltrative and obstructive disease on high-resolu-tion CT: differential diagnosis and functional correlates in a consecutive series. J Thorac Imaging 2001; 16:69–75

4. Whitten CR, Khan S, Munneke GJ, Grubnic S. A diag-nostic approach to mediastinal abnormalities. Radio-Graphics 2007; 27:657–671

5. Ferguson EC, Krishnamurthy R, Oldham SA. Classic imaging signs of congenital cardiovascular abnormali-ties. RadioGraphics 2007; 27:1323–1334

6. Marshall GB, Farnquist BA, MacGregor JH, Burrowes PW. Signs in thoracic imaging. J Thorac Imaging 2006; 21:76–89







1.5 CME1.0 SAM

Parker et al.


Scenario 1Clinical History

A 52-year-old woman presented to her primary care phy-sician with a several-week history of nonproductive cough, mild dyspnea, chest tightness, and wheezing (Fig. 1).

Description of ImagesFrontal chest radiography (Fig. 1A) shows an ill-defined left

perihilar opacity partially silhouetting the left heart border.

There is ipsilateral cephalad hilar displacement and broncho-vascular reorientation as well as leftward displacement of the tracheal air column. The left thorax appears smaller in vol-ume than the right. The left diaphragm is elevated and shows a juxtaphrenic peak. The left apex is hyperlucent, as is the left paramediastinal border. Note the luftsichel sign.

DiagnosisThe diagnosis is luftsichel sign of left upper lobe collapse

secondary to an obstructing endobronchial carcinoid tumor (Kulchitsky cell type I).

Solution to Question 1The radiographic features of pulmonary edema may in-

clude an increased cardiothoracic ratio, widening of the vas-cular pedicle, vascular redistribution or engorgement, dis-crepant arterial-to-bronchial ratios, interstitial Kerley lines, and possibly pleural effusions [1, 2]. Option A is not the best response because none of these signs is present. Pure pneu-monia is an air-space-replacing process characterized by an equal exchange of air in the alveoli for pus and thus preserva-tion of lung volume [3, 4]. Therefore, Option B is not the best response. Option D is not the best response because the loca-tion and morphology of the perihilar opacity support a pa-renchyma-based, not a mediastinum-based, lesion.

Option C, atelectasis, and left upper lobe atelectasis in par-ticular, is the best response. This case illustrates both direct and many indirect signs of volume loss. More important, the case shows the luftsichel sign. “Luftsichel,” which is German for “air crescent,” is an indirect sign of overinflation characterized by hyperexpansion of the superior segment of the left lower lobe and its insinuation between the collapsed upper lobe and the mediastinum. This particular imaging sign is seen in the setting of left upper lobe atelectasis and is a manifestation of compensatory overinflation in response to the upper lobe vol-ume loss [5]. Because of the absence of a horizontal fissure in the left thorax, as the upper lobe loses volume, the oblique fis-sure becomes vertically oriented in a plane roughly parallel to the anterior chest wall. The oblique fissure continues to shift further anteriorly and medially, with progressive volume loss until the atelectatic upper lobe is contiguous with the left heart border and partially silhouetting its border (i.e., the silhouette sign) and creating an ill-defined parahilar haze (i.e., the “veil sign”) on the frontal examination [5–8].

As the apical segment of the collapsing upper lobe moves anteromedially, the superior segment of the left lower lobe overinflates and fills in the vacated apex with aerated lung that can mimic an apical pneumothorax; option E is not the best response. However, the observation of additional indirect signs of volume loss, such as the juxtaphrenic peak, diaphrag-matic elevation, and the partial loss of definition of the left heart border, allow the appropriate differentiation. Addition-ally, a true pneumothorax can be confidently diagnosed by the recognition of a white visceral pleural line as opposed to a

QUESTION 1

What is the MOST LIKELY diagnosis?

A. Pulmonary edema.B. Pneumonia.C. Atelectasis.D. Mediastinal mass.E. Left apical pneumothorax.

A

Fig. 1—52-year-old woman with several-week history of nonproductive cough, mild dyspnea, chest tightness, and wheezing.A, Posteroanterior chest radiograph shows ill-defined left perihilar opacity partially silhouetting left heart border. Note ipsilateral cephalad hilar displace-ment and bronchovascular reorientation as well as leftward displacement of tracheal air column. Left thorax appears smaller in volume than right. Left diaphragm is elevated and shows juxtaphrenic peak. Left apex is hyperlucent, as is left paramediastinal border.


Thoracic Imaging

black edge due to a Mach effect [9, 10]. Such a white visceral pleural reflection is not present in this patient. Furthermore, a true visceral pleural reflection will also follow the contour of the lung periphery and not simply fade imperceptibly with the lung parenchyma, as was also seen in our patient [9, 10].

However, radiologists should be cautioned about the un-common relationship between lobar atelectasis and pneu-mothorax. A localized pneumothorax may occur adjacent to an atelectatic lobe and has been described as a sign of bronchial obstruction that is referred to as “pneumothorax ex vacuo.” In such cases, treatment should be directed to the underlying bronchus and not to the pleural space [11].

The overinflated superior segment of the lower lobe may insinuate itself between the collapsed upper lobe and the transverse aorta, creating a sharp crisp crescent or paraaor-tic radiolucency referred to as the luftsichel sign. The diag-nosis of left upper lobe collapse on single anteroposterior or posteroanterior chest radiographs can sometimes be diffi-cult. When a lateral chest radiograph is available (Fig. 1B), the diagnosis of left upper lobe collapse is more easily made by noting a retro sternal sigmoid-shaped band of increased opacity representing the anteriorly displaced oblique fissure

delineating the collapsed upper lobe from the overinflated lower lobe [5–8]. However, observing additional indirect signs of volume loss (e.g., ipsilateral mediastinal shift, hilar elevation, diaphragmatic elevation, juxtaphrenic peak, rib approximation, and so forth) will enable the radiologist to confidently make the best diagnosis, even in the absence of a lateral chest radiograph.

The luftsichel sign is a classic and helpful imaging finding on frontal chest radiography. Once lobar atelectasis has been identified, the cause (e.g., mucus plug, aspirated for-eign body, primary or secondary obstructing endobronchial tumors, and so forth) must be determined either through bronchoscopy or CT evaluation.

Endobronchial carcinoids are rare neuroendocrine tumors, accounting for approximately 2% of all lung neoplasms and 12–15% of all carcinoid tumors [12, 13]. These tumors origi-nate from bronchial mucosa neurosecretory cells and are classified as low-grade malignant neoplasms because of their potential for local invasion, local recurrence, and occasional metastasis [12, 13]. Endobronchial carcinoids have the po-tential to synthesize and secrete various peptide hormones and neuroamines (e.g., adrenocorticotropic hormone, sero-tonin, somatostatin, and bradykinin). These tumors are not associated with smoking [12–14]. Histologically, carcinoid tumors are categorized as either Kulchitsky cell carcinoma (KCC) type I (i.e., typical carcinoid) or KCC type II (i.e., atypical carcinoid). KCC type I is the classic endobronchial carcinoid and is the least aggressive [12, 13]. These lesions are usually well defined, are smaller than 2.5 cm in diameter, are located centrally in the mainstem bronchi, and affect rela-tively young patients, with a marked female predilection (10:1, females to males). Only 3% of typical carcinoid tu-mors metastasize to sites other than regional lymph nodes. The prognosis is excellent, with a 5-year survival rate of 92% [12–14]. KCC type II is the atypical carcinoid tumor and is responsible for 25% of pulmonary carcinoid tumors [12, 13]. These latter lesions tend to behave more aggressively, are larger, occur in peripheral locations, and usually affect older patients, with a male preponderance. Regional lymph node metastases are more common, occurring in up to 50% of pa-tients. Distant metastases to the liver, bone, and CNS occur in one third of patients [12–14]. The prognosis is less favor-able, with a 5-year survival rate of 69%. Surgical excision is the preferred treatment, typically lobectomy or pneumonec-tomy. Tracheobronchial sleeve resection may be used for cen-tral carcinoid lesions with normal distal lung parenchyma. CT can prospectively evaluate the likelihood of tumor resec-tion and is valuable in monitoring patients postoperatively for potential recurrence [12–14].

TreatmentThe treatment is left upper lobectomy. The patient has

since relocated and is now being followed up at another in-stitution. The current disease status is otherwise unknown.

Fig. 1—52-year-old woman with several-week history of nonproductive cough, mild dyspnea, chest tightness, and wheezing.B, Lateral chest radiograph shows retrosternal sigmoid-shaped band of increased opacity representing anteriorly displaced oblique fissure secondary to complete collapse of left upper lobe.

B

Parker et al.


QUESTION 2

Where is this lesion MOST LIKELY located?

A. Lung parenchyma.B. Mediastinum.C. Pleura.D. Chest wall.

Scenario 2

Clinical HistoryA 68-year-old asymptomatic nonsmoking woman under-

went preoperative screening chest radiography in prepara-tion for a total knee arthroplasty. The radiographic findings prompted subsequent chest CT (Fig. 2).

Description of ImagesA frontal chest radiograph (Fig. 2A) reveals a vague

opacity in the right midthorax overlying the fourth and fifth anterior ribs. The ribs appear intact. The inferior

margin of this mass is well delineated; however, the supe-rior margin is ill-defined or incomplete. On lateral chest radiography (Fig. 2B), the lesion appears better defined and is lentiform in morphology. The long axis of this mass parallels the long axis of the right oblique fissure. The an-terior, superior, and inferior borders appear better defined than the posterior border. Chest CT using the mediastinal window setting (Fig. 2C) reveals a large, slightly lobulated homogeneous mass. Two subtle punctuate hypervascular foci are seen in the periphery of the lesion. Lung window settings (Figs. 2D and 2E) confirm the lesion is localized to the right oblique fissure.

A

Fig. 2—68-year-old asymptomatic nonsmoking woman who underwent preoperative screening chest radiography in preparation for total knee arthroplasty. Radiographic findings prompted subsequent chest CT. A, Frontal chest radiograph reveals vague opacity in right midthorax overlying fourth and fifth anterior ribs. Ribs appear intact. Inferior margin of this mass is well delineated; however, superior margin is ill-defined or incomplete.B, On lateral chest radiograph, lesion appears better defined and is lentiform in morphology. Long axis of this mass parallels long axis of right oblique fissure. Anterior, superior, and inferior borders appear better defined than posterior border.


B

QUESTION 3


A. Primary lung cancer.B. Chest wall chondrosarcoma.C. Pseudotumor or vanishing tumor of the pleura.D. Localizedfibroustumorofthepleura.


Thoracic Imaging

C

Fig. 2 (continued)—68-year-old asymptomatic nonsmoking woman who underwent preoperative screening chest radiography in preparation for total knee arthroplasty. Radiographic findings prompted subsequent chest CT. C, Chest CT scan at mediastinal window setting reveals large, slightly lobulated homogeneous mass. Two subtle punctuate hypervascular foci are seen in periphery of lesion.D and E, CT images at lung window settings confirm lesion is localized to right oblique fissure.

D

E

DiagnosisThe diagnosis in this patient is localized fibrous tumor of

the pleura, as indicated by the incomplete border sign.

Solution to Question 2Extrapulmonary masses, when projected en face to the

x-ray beam, can simulate the presence of an intraparenchy-mal lesion [15]. The incomplete border sign illustrated in this patient is useful in distinguishing between extrapulmo-nary (options B, C, and D) and intrapulmonary (option A)

lesions. Option A is not the best response. Appropriate lo-calization is necessary before the proper differential diagno-sis can be determined.

Extrapulmonary masses often exhibit tapered or ovoid su-perior and inferior borders and are convex toward the lung [15]. The overlying pleura of extrapulmonary lesions smoothes out surface irregularities which, combined with the interface of the mass with lung air, give it a relatively sharply defined appearance [15]. However, this otherwise sharp bor-der may be lost where the mass becomes continuous with the

Parker et al.


pleura of the chest wall, thus forming an incompletely visu-alized border on radiography (Figs. 2A and 2B) and creating the so-called incomplete border sign [15–17].

Mediastinum- and chest wall–based masses may also show an incomplete border sign [15]. However, the location of this lesion on the frontal radiograph (Fig. 2A) would ar-gue against a mediastinal or chest wall cause. Options B and D are not the best responses. Localization of the lesion to the oblique fissure on the lateral chest radiograph (Fig. 2B) supports a pleural cause, which is subsequently con-firmed on CT (Figs. 2C–2E). Option C is the best response.

The most common extrapulmonary lesions include, but are not limited to, loculated pleural effusions, various rib lesions (e.g., fractures, primary and secondary tumors), mesenchymal tumors, neural tumors, hematomas, lipomas, and various cutaneous lesions (e.g., neurofibromas) [15].

Solution to Question 3The incomplete border sign supports a conclusion that

the lesion in question is extrapulmonary. Option A is not the best response.

Although chest wall metastases are the most common ma-lignant chest wall neoplasm in adults, chondrosarcoma is the most common primary malignant tumor of the adult chest wall [18–20]. Chondrosarcomas are malignant neoplasms with cartilaginous differentiation. Option B is not the best response. This neoplasm typically arises in the anterior chest wall and involves the sternum or costochondral cartilages. Less frequently, chondrosarcomas arise in the ribs (17%) and scapulae [18–20]. Chondrosarcomas occur across a wide age range but typically affect patients between the ages of 30 and 60 years. Most tumors manifest as palpable chest wall masses that may grow rapidly and become painful [18–20]. Males are affected slightly more frequently than females, in a ratio of 1.3:1.0 [18–20]. On radiologic imaging, variable intratumoral calcifications (e.g., rings, arches, flocculent, or stippled) can be identified, and osseous destruction is often present [18–20]. Surgical resection is the treatment of choice. The 5-year survival rate is more than 60% and may approach 80% in patients without metastases. Poor prognosis is associ-ated with incomplete tumor resection, metastases, local re-currence, and patient age older than 50 years [18–20].

Interlobar pleural fluid collections are typically ovoid or lentiform when viewed in tangent and may simulate a mass on conventional radiography [21]. The long axis of such

fluid collections is usually oriented along the long axis of the interlobar fissure [21]. Fluid has a tendency to accumu-late in the interlobar fissure in the setting of cardiac decom-pensation and to localize in the horizontal fissure in partic-ular [21]. The fluid collections tend to be spontaneously absorbed when the heart failure has been relieved and are therefore referred to as either pseudotumors or vanishing tumors of the pleura [21]. Option C is not the best response. Invariably, concomitant radiographic evidence of cardiac decompensation is seen or an ipsilateral pleural effusion is present [21].

Localized or solitary fibrous tumor of the pleura is a rare pleural neoplasm but is the second most common primary pleural neoplasm after malignant mesothelioma [22–24]. Option D is the best response. Although most of these tu-mors are related to the pleura, they have also been described in other intra- and extrathoracic locations. These tumors typically occur in adult men and women in the fifth through eighth decades of life. Many patients are asymptomatic and are diagnosed incidentally because of abnormal chest radiographic findings, as in our patient (Figs. 2A and 2B). Symptoms typically relate to tumor size and include cough, chest pain, and dyspnea. Hypertrophic pulmonary osteoar-thropathy is seen in 20–25% of patients. Symptomatic hy-poglycemia occurs in less than 5% of patients [22–24]. Ra-diographically, localized fibrous tumors of the pleura present as well-defined, variably sized, lobular extrapulmo-nary nodules or masses (i.e., incomplete border sign) and typically abut the pleura [23, 24] (Figs. 2A and 2B). CT re-veals a noninvasive lobular soft-tissue mass of variable size that abuts at least one pleural surface or may exhibit an interlobar fissure location (Figs. 2C–2E). Smaller lesions are more homogeneous in attenuation, whereas larger lesions may appear heterogeneous. Foci of calcification and en-hancing vessels may be observed in the lesion [23, 24] (Fig. 2C). These tumors are not related to mesothelioma, asbes-tos exposure, or tobacco abuse. Benign and malignant vari-ants have been described. Prognosis is related more to resec-tability than to histologic features [22–24].

TreatmentThe tumor was successfully resected in its entirety at

open thoracotomy. The patient remained disease-free at the time of the last follow-up CT examination 12 months before this writing.

Scenario 3

Clinical HistoryA 33-year-old man presented with a 3- to 4-day history

of dyspnea and a nonproductive cough. A chest radiograph (not shown) revealed bilateral perihilar air-space opacities with intervening normal aerated lung. He was admitted to the general medicine ward with a presumptive diagnosis

of community-acquired pneumonia and began taking levofloxacin. Over the next 3 days, he developed progres-sive hypoxia and was subsequently transferred to the in-tensive care unit for mechanical ventilation and nitric ox-ide therapy. Follow-up chest radiography (not shown) before intubation revealed progressive bilateral perihilar air-space disease. Subsequent chest CT pulmonary angi-ography on the same day did not show a pulmonary em-


Thoracic Imaging

bolus but did reveal an interesting pattern of air-space disease (Fig. 3).

Description of ImagesThe selected CT images (Fig. 3) through the upper, mid,

and lower lung zones reveal a patchy pattern of variable

attenuation characterized by a combination of ground-glass opacities, consolidations, reduced lung attenuation resulting from mosaic perfusion, and intervening normal lung. Note the “head cheese sign.”

DiagnosisThe diagnosis is Mycoplasma pneumonia with associated

bronchiolitis, as indicated by the head cheese sign.

Solution to Question 4The combination of mixed densities in the lung parenchy-

ma created by ground-glass opacities, air-space consolida-tions, reduced lung attenuation from mosaic perfusion, and intervening normal lung give the lung a geographic appear-ance on CT [25, 26] (Fig. 3). This pattern of mixed parenchy-mal lung densities has been likened to the morphologic ap-pearance of the mixture of boiled pork scraps and pigs’ feet

A

Fig. 3—33-year-old man with 3- to 4-day history of dyspnea and nonproductive cough. Chest radiograph (not shown) revealed bilateral perihilar air-space opaci-ties with intervening normal aerated lung. Patient was admitted to general medicine ward with presumptive diagnosis of community-acquired pneumonia and began taking levofloxacin. Over next 3 days he developed progressive hypoxia and was subsequently transferred to intensive care unit for mechanical ventilation and nitric oxide therapy. Follow-up chest radiograph (not shown) before intubation revealed progressive bilateral perihilar air-space disease.A–C, Selected chest CT pulmonary angiography images using lung window setting through upper (A), mid (B), and lower (C) lung zones reveal patchy pattern of variable attenuation characterized by combination of ground-glass opacities, consolidations, reduced lung attenuation resulting from mosaic perfusion, and intervening normal lung.

B

C

QUESTION 4

Which diagnosis would be LEAST LIKELY?

A. Sarcoidosis.B. Atypicalinfectionwithassociatedbronchiolitis.C. Hypersensitivity pneumonitis.D. Multiplesepticpulmonaryemboli.

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in a gelatinous background known and marketed as head cheese or hog’s head cheese and is therefore known as the “head cheese sign” or “hog’s head cheese sign” [25, 26]. How does this particular imaging sign help radiologists in their di-agnostic interpretation? CT must clearly show areas of ground-glass opacity and consolidation with concomitant mosaic perfusion (rather than one or the other) (Fig. 3). When these findings are present, they indicate a mixed infiltrative disease characterized by ground-glass or consolidation and an obstructive disease (usually associated with bronchiolitis) characterized by mosaic perfusion, with a decrease in vessel caliber and side branches in the hypoattenuating regions of lung parenchyma. The latter will often reveal air trapping on expiratory images [25–27]. The most common clinical causes of this CT pattern of disease include hypersensitivity pneu-monitis, sarcoidosis, atypical infections (e.g., those caused by Mycoplasma pneumoniae) with associated bronchiolitis, and acute interstitial pneumonia [25–27]. Options A, B, and C, which are likely diagnoses, are not the best responses. Addi-tional clinical and laboratory data would be necessary to fur-ther narrow the differential diagnosis. In this particular case, the diagnosis was an atypical infection with associated bron-chiolitis secondary to Mycoplasma pneumonia.

The CT pattern of multiple septic pulmonary emboli is much different. The latter disease process may be charac-terized by unilateral or bilateral areas of juxtapleural and wedge-shaped consolidation; diffuse, often angiocentric, nodules ranging from 0.5 to 3.5 cm in diameter, many of which show various stages of cavitation; and a peripheral rimlike pattern of enhancement after the administration of IV contrast media. Pleural effusions may also be identified in two thirds of patients, and 27% have identifiable hilar or mediastinal lymphadenopathy [28]. On the basis of the clinical presentation and the CT findings, Option D, multi-

ple septic pulmonary emboli, would be the least likely diag-nosis; therefore, option D is the best response.

Mycoplasmas are bacteria that lack a cell wall, adhere to ciliated respiratory epithelium, and produce hydrogen per-oxide, which damages epithelial cells and interferes with ciliary function. M. pneumoniae are one of three human pathogenic Mycoplasma species [29]. Bacteria are transmit-ted from person to person thorough aerosolized droplets. Infection may occur the year round but usually occurs dur-ing fall and winter [29, 30]. Patients may present with fever, chills, malaise, anorexia, sore throat, dry cough, and head-ache. As the disease progresses, nearly all patients develop an intractable hacking cough, but only 3% of such patients develop pneumonia. Extrapulmonary features are common and may include cervical lymphadenopathy, skin rash, aseptic meningitis, nausea, vomiting, and diarrhea. Rarely, patients present with or develop acute respiratory distress syndrome [29–31]. Such patients have higher morbidity and mortality rates. In these latter cases, supportive me-chanical ventilation is necessary in addition to corticoster-oids and antibiotic therapy (e.g., erythromycin, azithromy-cin, tetracycline, clarithromycin, and so forth) [29–31]. After infection, patients may fully recover; or interstitial fibrosis, bronchiectasis, Swyer-James syndrome, and im-paired pulmonary function may develop as sequelae of the infection [29, 30].

TreatmentTreatment is support with a mechanical ventilator and

nitric oxide therapy, corticosteroids, and clarithromycin. The patient was maintained on mechanical ventilation for 5 days and then was successfully extubated. Eight days later, he was discharged and was subsequently lost to follow-up.


A 35-year-old woman presented with fatigue, chest pain, and weight loss over the past several months (Fig. 4).

Description of ImagesA posteroanterior (Fig. 4A) chest radiograph shows a mas-

sively enlarged cardiomediastinal silhouette. Lateral chest radiography (not shown) showed complete obliteration of the retrosternal clear space. On closer inspection, the normal right and left pulmonary arteries and their respective interlo-

A

Fig. 4—35-year-old woman with fatigue, chest pain, and weight loss over past several months.A, Posteroanterior chest radiograph shows massively enlarged cardiomediasti-nal silhouette. Lateral chest radiograph (not shown) showed complete obliteration of retrosternal clear space. On closer inspection, normal right and left pulmonary arteries and their respective interlobar divisions can be identified well in what appears to be lateral or peripheral margin of cardiomediastinal silhouette.



Thoracic Imaging

bar divisions can be identified well in what appears to be the lateral or peripheral margin of the cardiomediastinal silhou-ette. Contrast-enhanced CT images (mediastinal window set-ting) through the main pulmonary artery level (Fig. 4B) and

the myocardium (Fig. 4C) show a large aggressive anterior mediastinal mass intimately related to the ascending aorta and main pulmonary artery with invasion of the myocardi-um proper. A small pericardial effusion is present.

DiagnosisThe diagnosis is malignant peripheral nerve sheath tu-

mor of the vagus nerve with mediastinal invasion, the hi-lum overlay sign.

Solution to Question 5The proximal segment of the visible left or right pulmo-

nary artery lies laterally to the cardiac silhouette or just within its edge on normal frontal chest radiography. As the myocardium enlarges in the setting of a cardio-myopathy or cardiomegaly or as the pericardial sac dis-tends with fluid from pericardial effusion, the pulmonary artery segments are simply displaced outward but con-tinue this same relationship to the cardiac silhouette [32, 33]. Options A and B are not the best responses. Alterna-tively, if either the left or right pulmonary artery can be seen 1.0 cm or more within the lateral edge of an opacity that appears to represent the cardiac silhouette, that opac-ity does not represent the cardiac silhouette and therefore cannot be the result of cardiomyopathy, cardiomegaly, or pericardial effusion, but is related instead to the presence of an anterior mediastinal mass [32, 33]. Option C is the best response. This is referred to as the hilum overlay sign, which can be used to determine that a lesion is extracar-diac and localized to the anterior mediastinal compart-

Fig. 4 (continued)—35-year-old woman with fatigue, chest pain, and weight loss over past several months.B and C, Contrast-enhanced chest CT scans using mediastinal window setting through main pulmonary artery level (B) and myocardium proper (C) show large aggressive anterior mediastinal mass intimately related to ascending aorta and main pulmonary artery as well as invasion of myocardium proper. Small pericardial effusion is present. DA = descending thoracic aorta, LLPA = left lower lobe pulmonary artery, PA = pulmonary artery, PV = pulmonary vein, RLPA = right lower lobe pulmonary artery, RA = right atrium, RV = right ventricle.

B C

QUESTION 5


A. Cardiomyopathy.B. Pericardial effusion.C. Anterior mediastinal mass.D. Pleural effusion.

QUESTION 6

All of the following are TRUE statements regarding the “hilum convergence sign” EXCEPT:

A. It differentiates a potential hilar mass from an enlarged pulmonary artery.

B. If the pulmonary arteries converge into the lateral borderoftheapparenthilarmass,themass represents an enlarged pulmonary artery.

C. Ifthepulmonaryarteriesconvergebehindthe apparenthilarmass,themassrepresentsan enlarged pulmonary artery.

D. If the convergence of the pulmonary arteries arisesfromthecardiacsilhouette,amediastinalmass is likely present.

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S10 AJR:192, March 2009

ment, thus steering the differential diagnosis in the appro-priate direction [32, 33]. Because the lesion of concern is mediastinum-based, option D, pleural effusion, is not the best response. It likewise would be quite unusual for pleu-ral effusion to present as perihilar ground-glass opacity. Additionally, the costophrenic angles are preserved. The mediastinal mass in this particular patient proved to be a malignant peripheral nerve sheath tumor (MPNST) aris-ing from the intrathoracic vagus nerve in the mediasti-num. MPNSTs are rare but aggressive sarcomas that arise from the nerve sheath or show features of nerve sheath differentiation; they more often involve the extremities, the head, and the neck. Intrathoracic MPNST is uncom-mon [34]. Although such tumors may occur in patients with neurofibromatosis 1 (von Recklinghausen’s disease) with an incidence of 0.16%, these tumors may also occur in patients with no signs of such (incidence of 0.001%), as in our patient [34–36]. Successful treatment requires complete surgical excision of the MPNST. Radiotherapy may delay recurrence but has little impact on patient survival. Con-ventional advanced soft-tissue sarcoma single-agent chemo-therapy with doxorubicin has a poor response rate [34].

Solution to Question 6Felson’s hilum convergence sign should be differentiated

from the hilum overlay sign discussed in the solution to ques-tion 5 [32]. The hilum convergence sign is useful in distinguish-ing between a large pulmonary artery and a hilar mass [32]. Because the pulmonary artery branches arise from the main pulmonary artery trunk, an enlarged pulmonary artery will have branches that arise from its lateral margin, and its vessels will appear to converge toward the main pulmonary artery [32]. Option B is the best response. A true hilar mass may have the appearance of an enlarged pulmonary artery, but the ves-sels will not arise from its lateral margin but rather seem to pass through the margin as they converge on the true pulmo-nary artery [32]. Therefore, if the convergence of the pulmo-nary arteries appears behind the apparent hilar mass or ap-pears to arise from the heart, a mediastinal mass is more likely [32]. Options A, C, and D are not the best responses.

TreatmentThe treatment, which was unsuccessful, was surgical de-

bulking of the tumor and palliative radiotherapy. The pa-tient died over the next several weeks.

Scenario 5

Clinical HistoryA 47-year-old man presented with chronic renal failure

and dyspnea (Fig. 5).

Description of ImagesA posteroanterior chest radiograph (Fig. 5A) shows

globular enlargement of the cardiomediastinal silhou-ette. There is an increase in transverse diameter of the cardiomediastinal silhouette but no increase in its height. The proximal segments of the visible left and right pul-monary artery lie laterally to the cardiac silhouette. A coned-down lateral chest radiograph (Fig. 5B) reveals separation of the black retrosternal fat stripe from the black epicardial fat stripe by an opaque interface. No

pleural effusion or interstitial edema is present. A con-trast-enhanced coronal maximum-intensity-projection chest CT scan (Fig. 5C) shows separation of the visceral and parietal pericardial layers by a large fluid collection surrounding the myocardium.

DiagnosisThe diagnosis is uremic pericardial effusion, the water

bottle sign.

Solution to Question 7A frontal chest radiograph (Fig. 5A) shows globular en-

largement of the cardiomediastinal silhouette with an in-crease in its transverse diameter but no increase in its height. As a result, the superior mediastinal borders appear straight-ened, giving the cardiomediastinal silhouette a morphology that has been likened to that of a water bottle, hence the designation “water bottle sign” [37, 38]. Applying the hi-lum overlay sign discussed in scenario 4, the proximal seg-ment of the visible left and right pulmonary artery contin-ues to lie laterally to the enlarged cardiac silhouette (i.e., negative hilum overlay), thus eliminating anterior mediasti-nal mass from diagnostic consideration. Option D is not the best response.

The pericardium consists of two layers. The visceral peri-cardium is attached to the surface of the myocardium and the proximal great vessels. The parietal pericardium forms the free wall of the pericardial sac [37–40]. The pericardial

QUESTION 7


A. Lobarpneumonia.B. Primary lung cancer.C. Acute heart failure.D. Anterior mediastinal mass.E. Pericardial effusion.

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Thoracic Imaging

sac itself normally contains 20–50 mL of fluid [37]. An ex-cess of pericardial fluid may accumulate in a number of set-tings. Option E is the best response. The most common cause is myocardial infarction with left ventricular failure [37]. Fifty percent of patients with chronic renal failure develop uremic pericardial effusions [37]. Other causes of peri-cardial effusion may include hypoalbuminemia, myxedema, infection, drug reactions, trauma, neoplasia, and autoim-mune disease [37]. The chest radiograph may appear rela-tively normal until the volume of pericardial fluid exceeds

250 mL [37–39]. The cardiomediastinal silhouette may then show symmetric enlargement and preservation of the nor-mal hilar relationships, resulting in the water bottle–shaped morphology [37–39] (Fig. 5A). A well-penetrating lateral chest radiograph is even more sensitive in the early detec-tion of pericardial effusion and may reveal separation of the retrosternal and epicardial fat stripe by more than 2 mm, which is sometimes referred to as the “Oreo [Nabisco] cookie sign,” “sandwich sign,” or “bun sign” [37–39] (Fig. 5B). The black epicardial and retrosternal fat stripes consti-

Fig. 5—47-year-old man with chronic renal failure and dyspnea.A, Posteroanterior chest radiograph shows globular enlargement of cardiomediastinal silhouette. Note increase in transverse diameter of cardiomediastinal silhouette but no increase in its height. Proximal segment of visible left and right pulmonary artery lies lateral to cardiac silhouette.B, Coned-down lateral chest radiograph reveals separation of black retrosternal fat stripe (single arrow) from black epicardial fat stripe (double arrows) by opaque interface. No pleural effusion or interstitial edema is present.C, Contrast-enhanced coronal maximum-intensity-projection chest CT scan at mediastinal window setting shows separation of visceral and parietal pericardial layers by large fluid collection surrounding myocardium.

A B

C

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tute the outer dark cookie layers or slices of bread in the sandwich or bun, and the opaque intervening pericardial fluid, the white fluff of the cookie or the meat in the sand-wich or bun. Although the cardiac silhouette is enlarged, the pulmonary vasculature appears normal, and signs of heart failure (e.g., vascular redistribution, Kerley B lines, and so forth) are absent (Fig. 5A). Option C is not the best response. CT is more sensitive in the detection of small peri-cardial effusions. Small effusions first collect dorsally to the left ventricle and along the left atrium. Larger effusions col-lect ventrally and laterally to the right ventricle. Very large effusions may envelop the myocardium, forming the “halo sign” [37, 40] (Fig. 5C). Lobar pneumonia and primary lung cancer are both air-space disease processes and are not ap-

propriate considerations in this patient. Options A and B are not the best responses.

Uremic pericardial effusion commonly improves with inten-sified or increased frequency of peritoneal or hemodialysis [41]. More aggressive management may be needed if the peri-cardial effusion is larger than 250 mL, if it continues to in-crease despite intensive dialysis for 10–14 days, or if the pa-tient develops tamponade [41, 42]. In these latter instances, pericardiocentesis, pericardial window, subxiphoid pericar-diotomy, or pericardiectomy may be necessary [41, 42].

TreatmentThe patient was successfully treated with a combination

of increased hemodialysis and subxiphoid pericardiotomy.


A 62-year-old woman presented with a long-standing his-tory of chronic atrial fibrillation; she had undergone cardiac surgery 7 days earlier (Fig. 6).

Description of ImagesA posteroanterior chest radiograph (Fig. 6A) shows an in-

creased cardiothoracic ratio. The pulmonary artery segment is enlarged, suggesting precapillary pulmonary hypertension. The aorta appears small from decreased forward cardiac out-

put. A convex bulge is present along the left heart border re-lated to left atrial chamber enlargement. Midline median ster-notomy wires can be delineated. A lateral chest radiograph (Fig. 6B) reveals a convex bulge in the superoposterior cardiac border below the carina, with posterior displacement of the left lower lobe bronchus and opacification of the retrocardiac clear space. Right ventricular enlargement encroaches on the retrosternal clear space. Foci of residual pneumomediastinum and a retained subxiphoid pacer lead can be seen in the retro-sternum. A newly placed mitral valve prosthesis is present. Thin curvilinear calcifications can also be seen paralleling the

Fig. 6—62-year-old woman with long-standing history of chronic atrial fibrillation. Patient had undergone cardiac surgery 7 days earlier.A, Posteroanterior chest radiograph shows increased cardiothoracic ratio. Pulmonary artery segment is enlarged, suggesting precapillary pulmonary hyperten-sion. Aorta appears small from decreased forward cardiac output. Convex bulge is present along left heart border related to left atrial chamber enlargement. Midline median sternotomy wires can be delineated.B, Lateral chest radiograph shows relative posterior displacement of left upper and lower lobe bronchus relative to right (arrows), forming “walking man sign.” Right ventricular enlargement encroaches on retrosternal clear space. Foci of residual pneumomediastinum and retained subxiphoid pacer lead can be seen in retrosternum. Newly placed mitral valve prosthesis is present. Thin curvilinear calcifications can also be seen paralleling posterior wall of enlarged left atrium. No radiographic evidence of acute cardiac decompensation is seen.

A B

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Thoracic Imaging

posterior wall of the enlarged left atrium. No radiographic evidence of acute cardiac decompensation is seen.

DiagnosisThe diagnosis is mitral stenosis and left atrial calcifica-

tion, as indicated by the walking man sign.

Solution to Question 8Although the cardiothoracic ratio is enlarged, the vascular

pedicle is not widened and there is no radiographic evidence of vascular redistribution or septal lines to support a diagno-sis of acute heart failure (Fig. 6). Option A is not the best response. Ebstein anomaly is a congenital heart malforma-tion manifested by apical displacement of the septal and pos-terior tricuspid valve leaflets, leading to atrialization of the right ventricle and a variable degree of malformation and displacement of the anterior leaflet [43]. Although chest ra-diography may be normal in patients with Ebstein anomaly, characteristic radiologic features include right atrial enlarge-ment, which may occasionally be quite severe; inferior vena cava and azygos dilatation secondary to tricuspid regurgita-tion; hypoplasia of the aorta and main pulmonary artery; and a normal-sized left atrium [44]. These radiographic fea-tures are not present in this patient (Fig. 6). Option B is not the best response. Although mitral valve prolapse may be as-

sociated with cardiac dysrhythmias, enlargement of the left atrium (Fig. 6) is uncommon except in cases of prolapse com-plicated by severe mitral regurgitation [45, 46]. Option D is not the best response.

Mitral stenosis is characterized by narrowing of the inlet valve orifice of the left ventricular chamber, which interferes with normal opening during diastole [37, 47–49]. Option C is the best response. Affected patients typically have thickened valve leaflets, fused commissures, or thickened and shortened chordae tendineae. The normal mitral valve orifice area is 4–6 cm2 [47–49]. In early diastole, a small pressure gradient exists between the atrium and the ventricle, but during most of di-astole the pressures in these two chambers are relatively simi-lar. When the mitral valve area narrows to less than 2.5 cm2, blood flow is impeded, which causes an increase in left atrial pressure. Critical mitral stenosis occurs when the area is re-duced to 1 cm2 [47–49]. When this occurs, a left atrial pressure of at least 25 mm Hg is necessary to maintain normal cardiac output [47–49]. The increase in left atrial pressure enlarges the left atrium and increases pulmonary venous and capillary pressures, resulting in pulmonary venous congestion and re-duced cardiac output. This scenario can mimic left ventricular failure, but left ventricular contractility is usually normal. Chronic atrial fibrillation commonly ensues as the left atrium enlarges [50]. Chronic elevation of left atrial pressures leads to pulmonary artery hypertension, tricuspid and pulmonary valve incompetence, right ventricular hypertrophy (Fig. 6) and, eventually, right heart failure [37, 47–49]. In cases of long-standing mitral stenosis, the left atrial wall may rarely calcify (Fig. 6B). Such calcification is more common in pa-tients with endocarditis resulting from rheumatic heart dis-ease; most affected patients also have heart failure and chron-ic atrial fibrillation [51]. Calcification of the mitral valve itself occurs in approximately 10% of affected patients. This should not be confused with mitral annulus calcification. Calcifica-tion of the mitral valve annulus does not indicate underlying mitral stenosis and is often a finding of senescence [37, 49].

Solution to Question 9The term “coeur en sabot” refers to a heart that has a boot-

shaped morphology as a result of uplifting of the cardiac apex because of right ventricular hypertrophy and the ab-sence of a normal main pulmonary artery segment [44]. This is a feature on frontal chest radiographs most often associated with tetralogy of Fallot. Additional radiologic features of this congenital cardiac malformation include decreased pulmo-nary vascularity; a normal-sized heart because of the lack of pulmonary blood flow and heart failure; right atrial enlarge-ment; and, in approximately 20–25% of affected patients, a right-sided aortic arch [44]. Option A is not the best response. The “double density sign” is an early radiologic feature of left atrial enlargement seen on frontal, not lateral, chest radio-graphs [52]. Option C is not the best response. This imaging sign manifests as an interface projecting over the right retro-

QUESTION 8


A. Acute heart failure.B. Ebsteinanomaly.C. Mitral stenosis.D. Mitral valve prolapse.

QUESTION 9

Which imaging sign is demonstrated on the lateral chest radiograph (Fig. 6B)?

A. Coeurensabotsign.B. Walking man sign.C. Doubledensitysign.D. Doughnut sign.

QUESTION 10

What is the principal cause of acquired mitral stenosis?

A. Rheumatic heart disease.B. Left atrial myxoma.C. Leftatrialthrombus.D. Maternalingestionoflithiuminthefirsttrimester

of pregnancy.

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S14 AJR:192, March 2009

cardiac region (Fig. 6A). The interface represents the inferior margin of the enlarged left atrium as it pushes into the adja-cent lung [52]. On frontal radiographs of adult patients, a left atrial dimension—defined as the distance from the midpoint of the double density to the inner margin of the left main-stem bronchus—greater than 7 cm suggests left atrial en-largement is present [52]. However, this sign and these dimen-sions are not reliable in pediatric patients [52]. The double density sign is often associated with splaying of the normal carinal angle of 60–90° and divergence of the caudal main-stem bronchi, creating a somewhat “wishbone” morphology in severe cases [52]. These latter two signs are best appreciat-ed on well-exposed or well-penetrating frontal examinations. The “doughnut sign” is an imaging sign seen on lateral chest radiography; however, it suggests the presence of mediastinal lymphadenopathy, not cardiac valvular disease [53, 54]. Op-tion D is not the best response. On normal chest radiography, the aortic arch and the right and left pulmonary arteries cre-ate an inverted horseshoe appearance [53, 54]. Subcarinal lymphadenopathy obliterates the notch in the horseshoe, forming a rounded circle likened to the morphology of a bagel or doughnut [53, 54].

The normal trachea, right and left upper lobe bronchi, and lower lobe bronchi are vertically aligned on a normal lateral chest radiograph. The walking man sign is a lateral chest radi-ography sign that is seen with posterior displacement of the left upper or lower lobe bronchus relative to the right bronchi, so that the bronchial relationship resembles the legs of a man in midstride [55]. Option B is the best response. Posterior dis-placement of the left bronchi is typically the result of mass effect on the bronchi by a markedly enlarged left atrium but is not pathognomic of an enlarged atrium [55]. The walking man sign may also occur in the setting of subcarinal lymphadenop-athy, mediastinal masses, left lower lobe volume loss, large hi-atal hernias, and thoracolumbar scoliosis.

Solution to Question 10Although it is rare today, mitral stenosis is still most com-

monly caused by rheumatic fever [5–8]. Option A is the best response. Approximately 40% of patients with rheumatic heart disease have isolated mitral valve stenosis. However, rheumatic involvement is identified in 99% of stenotic mitral valves examined at the time of valve surgery [47–49]. Other, less frequent, causes of mitral stenosis include congenital stenosis, an obstructing lesion such as a left atrial myxoma, atrial thrombus, systemic lupus erythematosus, rheumatoid arthritis, malignant carcinoid, various mucopolysaccharidos-es, Fabry’s disease, Whipple’s disease, and methysergide ther-apy [37, 47–49]. Options B and C are not the best responses. Although it is somewhat controversial, maternal ingestion of lithium, ingestion of benzodiazepines, and exposure to various varnishing agents in the first trimester of pregnancy have been reported to be associated risk factors for Ebstein anomaly [56, 57]. Option D is not the best response.

Balloon valvotomy is usually the initial procedure of choice for symptomatic patients with moderate to severe mitral stenosis. Valvotomy can double the mean valve area, with a 50–60% decrease in the transmitral gradient, which provides symptomatic improvement. Surgical commissurotomy has a similar efficacy to that of balloon valvotomy but is usually reserved for patients with left atrial thrombus despite antico-agulation or a nonpliable or calcified valve. Mitral valve re-placement is reserved for patients who are not candidates for either percutaneous balloon mitral valvotomy or surgical commissurotomy [58, 59]. Lifelong endocarditis antibiotic prophylaxis is recommended for procedures that may be as-sociated with transient bacteremia (e.g., dental procedures, bronchoscopy, colonoscopy, cystoscopy, and so forth) [58–60].

TreatmentThe treatment is mitral valve replacement. The patient

was discharged on postoperative day 7. We have no addi-tional information on her current clinical status.

ConclusionThis case-based self-assessment module describes several

important radiologic signs that are useful in diagnosing vari-ous diseases affecting the chest, including the luftsichel sign of left upper lobe collapse; the incomplete border sign of pleural and chest wall-based lesions; the head cheese sign or hog’s head cheese sign of atypical infection with associated bronchiolitis, sarcoidosis, acute interstitial pneumonitis, and hypersensitivi-ty pneumonitis; the hilum overlay sign, which is useful in local-izing lesions to the anterior mediastinum; the hilum conver-gence sign that distinguishes an enlarged pulmonary artery from a true hilar mass; the water bottle sign and the Oreo cookie sign of pericardial effusion; and the walking man sign of left atrial enlargement. Future articles will continue this discussion of additional useful signs in thoracic imaging that can be applied to assist the radiologist in establishing the cor-rect diagnosis or differential diagnosis in applicable cases.

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AJR Teaching File: Right Atrial Mass in a Woman with Dyspnea on ExertionBenjamin J. Holloway1, Prachi P. Agarwal2

Keywords: cardiac imaging, heart neoplasm, MRI

DOI:10.2214/AJR.07.7066

Received December 27, 2007; accepted after revision April 7, 2008.1Department of Radiology, University Hospital Birmingham NHS Foundation Trust, Metchley La., Birmingham, West Midlands, B67 5HR, United Kingdom. Address correspondence to B. J. Holloway ([email protected]).2Department of Radiology, Division of Cardiothoracic Radiology, University of Michigan, Ann Arbor, MI.


Case HistoryA 50-year-old woman presents with nonspecific chest

pain, a syncopal episode, and increasing dyspnea on exer-tion without edema, orthopnea, or paroxysmal nocturnal dyspnea. CT pulmonary angiography is performed to evalu-ate for pulmonary embolism. This is followed by cardiac MRI to further evaluate abnormal cardiac findings identi-fied on CT pulmonary angiography. CT of the abdomen that was performed 7 months previously to investigate up-per abdominal pain is also reviewed and found to include the area of abnormality.

Radiologic DescriptionInitial contrast-enhanced abdominal CT shows subtle

thickening of the inferior right atrial wall near the dia-phragm that was only appreciated in retrospect (Fig. 1A). Subsequent CT pulmonary angiography performed 7 months later using 120 kVp, 150 mA, and 1.25-mm slice thickness after the administration of 125 mL of the non-ionic IV contrast material iopromide (Ultravist 300, Bayer HealthCare) at 4 mL/s, reveals the dramatic rapid growth of a large soft-tissue mass centered on the right atrial free wall along with a right pleural effusion. The right lower lobe lung nodule was one of several similar lesions in the lungs (Fig. 1B). On cardiac MRI, the cine balanced steady-state free precession (balanced SSFP) sequence (TR/TE, 2.9/0.99) in four-chamber orientation shows a lobulated mass extend-ing into and nearly obliterating the right atrial cavity but without involvement of the interatrial septum (Fig. 1C and video, Fig. S1C, in supplemental data at www.ajronline.org). The mass is predominantly isointense on axial ECG-gated breath-hold T1-weighted double inversion recovery fast spin-echo sequence (667/41) with a few areas of scat-tered hyperintensity compatible with hemorrhage (Fig. 1D) and has a heterogeneously hyperintense appearance on T2-weighted images (1,364/101) (Fig. 1E). The mass extends into the atrioventricular groove and encases the right coro-nary artery. On first-pass perfusion imaging with a gadolin-ium-based contrast agent (0.1 mmol kg of gadopentetate dimeglumine), marked peripheral linear and nodular tumor

enhancement is evident (Fig. 1F and video, Fig. S1F, in sup-plemental data).

Differential DiagnosisThe differential diagnosis of a right atrial mass includes

benign entities such as myxoma and thrombus and malig-nant causes such as metastatic involvement of the heart, primary cardiac angiosarcoma and other sarcomas, peri-cardial mesothelioma, and primary cardiac lymphoma.

DiagnosisThe diagnosis, based on biopsy of one of the lung metasta-

ses showing spindle cells, is primary cardiac angiosarcoma.

CommentaryMetastases are by far the most common cardiac neo-

plasms, 40 times more prevalent than primary cardiac tu-mors [1]. Primary cardiac tumors are rare lesions and in-clude both benign and malignant histologic types, with myxomas being the most common [2]. Primary malignant cardiac tumors include angiosarcoma, undifferentiated sar-coma, rhabdomyosarcoma, osteosarcoma, leiomyosarcoma, and primary cardiac lymphoma [1].

Angiosarcomas, although rare, are the most common pri-mary malignant neoplasms of the heart, making up more than a third of cardiac sarcomas [1, 3]. Cardiac angiosarcomas present in adults around middle age, with cases in children and infants being rare. Males are more commonly affected. The clinical signs and symptoms are often nonspecific. Because of the propensity of the tumor to involve the right atrium and pericardium, patients may present with right-sided heart fail-ure and tamponade [3, 4]. There is frequently metastatic spread at presentation, most commonly to the lungs, but also occasionally to lymph nodes, bone, liver, brain, bowel, spleen, adrenal glands, pleura, diaphragm, kidneys, thyroid, and skin [5]. The prognosis is universally poor; patients rarely survive beyond a year despite treatment [6]. In most cases, angiosar-comas involve the right atrial free wall [7] as a well-defined mass protruding into the right atrium and usually sparing the interatrial septum. CT and MRI can both show tumor infiltra-

Holloway and Agarwal


tion of the myocardium and direct extension into the pericar-dium [4]. The second, rarer subtype, is a diffusely infiltrative mass extending along the pericardium [4].

Initial evaluation is usually performed using echocardio-graphy, which may be limited by factors such as operator de-pendence, restricted field of view, and unfavorable body habi-tus. Cardiac MRI enables the most comprehensive imaging assessment of cardiac neoplasms. In contrast to transthoracic echocardiography, cardiac MRI provides improved soft-tissue

contrast, tissue characterization, and assessment of mediasti-nal and lung involvement by the tumor. The addition of imag-ing with a gadolinium-based contrast agent allows an assess-ment of the extent of tumor vascularity and further improves the differentiation from surrounding structures.

Angiosarcomas appear as irregular lobulated low-attenua-tion masses on CT that frequently extend to involve the adja-cent pericardium and vessels. On MRI, they exhibit hetero-geneous signal on T1- and T2-weighted sequences, which is

A

C

Fig. 1—50-year-old woman with shortness of breath and chest pain.A, Axial contrast-enhanced CT scan of abdomen shows subtle thickening of inferior right atrial wall. d = dome of diaphragm.B, Subsequent CT pulmonary angiography image 7 months later reveals dramatic growth of large lobulated mass centered on right atrial wall, new subpleural right lower lobe lung nodule (arrow) that is one of many, and right pleural effusion. d = dome of diaphragm.C, Four-chamber balanced steady-state free precession image shows lobulated mass extending into and nearly obliterating right atrial cavity but without involve-ment of interatrial septum. (See also supplemental video, Fig. S1C, at www.ajronline.org.)D, Axial ECG-gated breath-hold T1-weighted double inversion recovery fast spin-echo image shows predominantly isointense mass with a few areas of scattered hyperintensity compatible with hemorrhage.


B

D


Right Atrial Mass

statistically the most common primary malignant tumor and arises most commonly in the right atrial free wall. Most other cardiac sarcomas, such as undifferentiated sarcoma, leiomyo-sarcoma, and fibrosarcoma, have a propensity to involve the left atrium, an important differentiating feature [5]. Rhab-domyosarcoma, the most common primary cardiac tumor in children, does not have any chamber predilection [4].

Cardiac lymphoma is far more commonly seen as secondary myocardial involvement related to extensive systemic disease. Primary cardiac lymphoma—the absence of extracardiac dis-ease at the time of diagnosis—is rare [5]. The primary form usually occurs in immunocompromised individuals and favors the right heart, as does angiosarcoma. However, lymphoma is less likely to involve cardiac valves, show necrosis, or extend into the cardiac chamber than angiosarcoma [11].

Pericardial mesothelioma is thought to be a distinct en-tity and not an extension of pleural mesotheliomas into the pericardium [5]. Pericardial mesothelioma encases the heart and resembles metastatic involvement of the pericardium [5]. Frank invasion of the epicardium is rarely seen [1].

ObjectiveThe educational objective of this article is to describe the

MRI features of cardiac angiosarcoma and to highlight the features differentiating it from other cardiac masses.

ConclusionCardiac angiosarcomas, although rare, are the most com-

mon primary malignant cardiac tumors. The location of the tumor on the right atrial wall, its heterogeneous infiltra-tive appearance, and its enhancement are important diag-nostic features. The tumor is aggressive, and metastases to

thought to relate to hemorrhage, necrosis, and flow voids in the tumor. These areas of high signal intensity interspersed with areas of intermediate signal have been described as a cauliflower appearance [8]. After administration of the gad-olinium-based contrast agent, the tumor enhances heteroge-neously and shows marked surface enhancement [1]. A sun-ray appearance has also been described in cases with diffuse pericardial enhancement as multiple lines emanating from the epicardium to pericardium [9].

In our patient, a benign neoplasm—the most common being a myxoma—or a nonneoplastic lesion such as throm-bus are unlikely in view of the infiltrative nature of the mass and the development of multiple new lung nodules, which are consistent with metastases. Also, the marked pe-ripheral enhancement on the first-pass imaging is in keep-ing with a highly vascularized tumor. Although heteroge-neous signal characteristics are common to both myxomas and angiosarcomas, the former are generally more well-de-fined, often with a stalk; tend to involve the interatrial sep-tum; and are more common in the left atrium [10].

The most common malignant cardiac tumor is cardiac me-tastasis, which can result from direct extension, hematoge-nous or venous extension, or retrograde flow by lymphatic vessels. However, these manifest in patients with known non-cardiac primary malignancy and widespread systemic dis-ease. The most common malignancies metastatic to the heart are lung and breast cancers, lymphoma, and leukemia, with the pericardium rather than the myocardium being the most common site of involvement. Only about 5% of metastases are estimated to be endocardial or intracavitary lesions [5].

Differentiating angiosarcoma from other primary malig-nant cardiac neoplasms can be challenging. Angiosarcoma is

E

Fig. 1 (continued)—50-year-old woman with shortness of breath and chest pain.E, Heterogeneous hyperintense appearance is seen on axial ECG-gated breath-hold T2-weighted double inversion recovery fast spin-echo image.F, First-pass perfusion image using fast gradient-echo echo-train pulse sequence shows marked peripheral linear and nodular enhancement. (See also supplemen-tal video, Fig. S1F, at www.ajronline.org.)

F

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the lungs are frequently discovered at presentation. The long-term prognosis is universally poor.

References 1. Sparrow PJ, Kurian JB, Jones TR, Sivananthan MU. MR imaging of cardiac

tumors. RadioGraphics 2005; 25:1255–1276

2. Reynen K. Frequency of primary tumors of the heart. Am J Cardiol 1996; 77:107

3. Burke A, Virmani R. Tumors of the heart and great vessels. In: Atlas of tumor pathology, fasc 16, ser 3. Washington, DC: Armed Forces Institute of Pathol-ogy, 1996

4. Araoz PA, Eklund HE, Welch TJ, Breen JF. CT and MR imaging of primary cardiac malignancies. RadioGraphics 1999;19:1421–1434

5. Grebenc ML, Rosado de Christenson ML, Burke AP, Green CE, Galvin JR. Primary cardiac and pericardial neoplasms: radiologic–pathologic correlation.

RadioGraphics 2000; 20:1073–1103

6. Burke AP, Cowan D, Virmani R. Primary sarcomas of the heart. Cancer 1992; 69:387–395

7. Best AK, Dobson RL, Ahmad AR. Best cases from the AFIP: cardiac angiosar-coma. RadioGraphics 2003; 23[spec no]:S141–S145

8. Kim EE, Wallace S, Abello R, et al. Malignant cardiac fibrous histiocytomas and angiosarcomas: MR features. J Comput Assist Tomogr 1989; 13:627–632

9. Yahata S, Endo T, Honma H, et al. Sunray appearance on enhanced magnetic resonance image of cardiac angiosarcoma with pericardial obliteration. Am Heart J 1994; 127:468–471

10. Grebenc ML, Rosado-de-Christenson ML, Green CE, Burke AP, Galvin JR. Cardiac myxoma: imaging features in 83 patients. RadioGraphics 2002; 22:673–689

11. Luna A, Ribes R, Caro P, Vida J, Erasmus JJ. Evaluation of cardiac tumors with magnetic resonance imaging. Eur Radiol 2005; 15:1446–1455

F O R Y O U R I N F O R M A T I O N

A data supplement for this article can be viewed in the online version of the article at: www.ajronline.org.




AJR Teaching File: Right Atrial Mass in a Woman with Uterine FibroidsSamah Jan1, Evan H. Dillon, Neal F. Epstein

Keywords: cine MRI, CT, heart, MRI, uterine fibroids, vascular system, venography, women’s imaging

DOI:10.2214/AJR.07.7080

Received February 28, 2008; accepted after revision April 7, 2008.1All authors: Department of Radiology, Lenox Hill Hospital, 100 E 77th St., New York, NY 10075. Address correspondence to E. H. Dillon ([email protected]).


Case HistoryA 48-year-old woman with a history of hypertension who

had undergone dilatation and curettage for vaginal bleeding related to uterine fibroids presents with palpitations and chest pain. A heart murmur is detected on physical exami-nation. Echocardiography performed elsewhere depicted a possible right atrial myxoma with inferior vena caval in-volvement. She was then referred to our institution for fur-ther evaluation and treatment.

Radiologic DescriptionCT of the abdomen and pelvis was requested to assess the

degree of inferior vena caval obstruction produced by the right atrial mass detected on the echocardiogram. Images were obtained before and after the administration of intra-venous contrast material. Axial and coronal reformatted images were produced. The unenhanced images depicted no visible abnormality in the right atrium or inferior vena cava. The contrast-enhanced images depicted a continuous tubular filling defect projecting within the lumen of the right atrium and within the lumen of the inferior vena cava and extending inferiorly to the level of the confluence of the iliac veins (Figs. 1A–1C). No definite iliac vein involve-ment was depicted. The tubular filling defect had a visual-ized length of 20.8 cm and a transverse diameter of 0.5 cm. It appeared to have a small central focus of enhancement. Images of the pelvis showed the uterus to be markedly en-larged and extending superiorly to the level of the L4 verte-bral body (Figs. 1D and 1E). Multiple focal heterogeneous myometrial lesions were identified with an appearance con-sistent with uterine leiomyomas.

MRI of the heart was performed to provide further assess-ment of the right atrial mass seen on the echocardiogram. Images were obtained in multiple planes both with and with-out gadolinium. These images confirm the presence of a tu-bular filling defect extending into the right atrium from the inferior vena cava (Figs. 1F and 1G). The abnormality was best visualized on the cine MR images using a white blood steady-state free precession (SSFP) pulse sequence (FIESTA [GE Healthcare]: fast imaging employing steady-state acqui-sition sequence on a GE Healthcare Signa 1.5-T MRI scan-

ner) without gadolinium. These cine images revealed that the filling defect was not attached to the wall of the right atrium or inferior vena cava. Instead, it was shown to move freely within the lumen of the right atrium and within the lumen of the inferior vena cava on images obtained during different phases of the cardiac cycle. During diastole, the mass ap-peared to prolapse across the tricuspid valve (Figs. 1H and 1I). MRI confirmed the central focus of flow in the center of the tubular structure (Fig. 1F).

An inferior vena cavagram was obtained using a right common iliac vein injection followed by a left common iliac vein injection. These images showed a long mobile filling defect extending from the left internal iliac vein into the left common iliac vein and up the length of the inferior vena cava (Fig. 1J).

Differential DiagnosisAn apparent filling defect in the inferior vena cava ex-

tending into the right atrium may be artifactual or actual [1, 2]. The most common artifactual filling defect is pseudo-thrombosis produced by an admixture of opacified and un-opacified blood. Actual filling defects include bland throm-bus and tumor thrombus. Bland thrombus may be idiopathic or may result from a hypercoagulable state. Tu-mor thrombus is most commonly seen with malignant tu-mors, including renal and hepatic tumors, that extend into the inferior vena cava but may also be seen with benign tu-mors, including intravenous leiomyomatosis, renal angio-myolipoma, and adrenal pheochromocytoma.

DiagnosisThe diagnosis is tumor thrombus due to intravenous leio-

myomatosis with angioid features extending from uterine leiomyomata. This patient first underwent an open resection of the intracardiac and intravascular portions of the tumor through a right atrial approach. The pathology specimen from that surgery revealed intravenous leiomyomatosis. Sub-sequently, the patient underwent a supracervical hysterecto-my and bilateral salpingo-oophorectomy. The pathology specimen from that surgery revealed extensive uterine leio-myomatosis as well as intravenous leiomyomatosis with focal vascular thrombosis. The cut surfaces of the myometrium

Jan et al.


revealed branching vascular spaces filled with gelatinous ma-terial and wormlike structures. Immunohistochemical stains showed strong diffuse labeling in tumor cell nuclei for proges-terone receptor and smooth muscle actin, whereas staining for estrogen receptor was weak and focal.

CommentaryIntravenous leiomyomatosis is a rare benign tumor char-

acterized by proliferation of smooth muscle cells in the veins [3, 4]. The tumor may arise directly from the wall of the vein but more commonly occurs as a result of growth of uterine leiomyomata into the myometrial veins [5]. From the myometrial veins, intravenous leiomyomatosis may

spread to the pelvic veins, inferior vena cava, right atrium, right ventricle, and pulmonary artery [4–6]. Involvement of the adrenal and renal veins has also been reported [5].

Intravenous leiomyomatosis is one of the unusual growth patterns of histologically benign uterine leiomyo-mata [4]. Other unusual growth patterns of uterine leio-myomata include parasitic leiomyoma, disseminated peri-toneal leiomyomatosis, diffuse leiomyomatosis, and benign metastasizing leiomyoma. Although they are histological-ly benign, these aggressive growth patterns resemble the behavior of malignant tumors.

Intravenous leiomyomatosis is seen almost exclusively in white women in the age range of 28–80 years (median age,

A

C

Fig. 1—48-year-old woman with palpitations, chest pain, heart murmur, and right atrial mass seen on echocardiography. A and B, Axial contrast-enhanced CT scans at level of suprahepatic (A) and suprarenal (B) portions of inferior vena cava show filling defect in inferior vena cava with central enhancement (arrows).C, Coronal contrast-enhanced CT scan shows thin linear filling defect (arrows) extending throughout length of inferior vena cava.


B


Right Atrial Mass

D

F

Fig. 1 (continued)—48-year-old woman with palpitations, chest pain, heart murmur, and right atrial mass seen on echocardiography. D and E, Axial (D) and coronal (E) contrast-enhanced CT scans of mid pelvis show uterus to be markedly enlarged, lobulated, and heterogeneous, an appearance that likely represents presence of multiple uterine leiomyomas.F, Oblique axial cine MR image at level of suprahepatic portion of inferior vena cava (IVC) using white blood steady-state free precession (SSFP) pulse sequence (FIESTA [GE Healthcare]: fast imaging employing steady-state acquisition sequence) without gadolinium shows filling defect (arrow) in inferior vena cava with cen-tral flow.G, Oblique sagittal cine MR image of heart and intrahepatic portion of IVC using white blood SSFP pulse sequence (FIESTA) without gadolinium shows filling defect (arrows) extending from inferior vena cava into right atrium.


E

G

Jan et al.


44 years). It typically occurs in parous women before meno-pause [5, 7]. Most patients with intravenous leiomyomato-sis have a history of uterine leiomyoma leading to hysterec-tomy, often many years earlier [5, 7]. Patients with intra venous leiomyomatosis may present with symptoms related to uterine leiomyomata, such as pelvic pain or vaginal bleed-ing [5]. They may also present with symptoms of inferior vena cava obstruction such as lower extremity edema. If the tumor extends into the heart, the patient may present with heart failure, dyspnea on exertion, pulmonary embo-lism, syncope, or sudden death [5, 7]. Physical examination

may reveal a heart murmur related to partial obstruction of the tricuspid valve [7].

The first imaging study is often echocardiography to eval-uate a heart murmur. On echocardiography, a mass may be visible in the right atrium, as occurred in our patient. Careful inspection will reveal that the mass extends into the right atrium from the inferior vena cava. Subsequent studies often include CT and MRI. On contrast-enhanced CT and MRI, an enhancing mobile intraluminal filling defect is usually depict-ed. Establishing the diagnosis on CT or MRI depends on vi-sualizing the connection between the intravenous mass and

H

J

Fig. 1 (continued)—48-year-old woman with palpitations, chest pain, heart murmur, and right atrial mass seen on echocardiography. H, Axial cine MR image at level of right atrium using white blood SSFP pulse sequence (FIESTA) without gadolinium shows filling defect (arrow) along right lateral wall of right atrium during systole.I, Axial cine MR image at level of right atrium using white blood SSFP pulse se-quence (FIESTA) without gadolinium shows filling defect (arrow) prolapsing across tricuspid valve during diastole.J, Inferior vena cavagram obtained using left common iliac vein injection shows linear filling defect (arrows) extending from left internal iliac vein into left com-mon iliac vein and up into inferior vena cava.

I


Right Atrial Mass

the uterus [5]. However, in most patients who have previ-ously undergone hysterectomy, that connection cannot be shown. If the previous hysterectomy specimen showed a pathologic diagnosis of intravenous leiomyomatosis, then it is likely that a subsequently visualized intravenous mass rep-resents recurrence and spread of intravenous leiomyomato-sis. The differential diagnosis of intravenous leiomyomatosis includes other causes of tumor thrombus such as renal cell carcinoma, hepatocellular carcinoma, adrenocortical carci-noma, pancreatic carcinoma, Wilms’ tumor, renal angiomyo-lipoma, and adrenal pheochromocytoma [1, 5].

Treatment consists of complete surgical excision of the in-travenous tumor along with hysterectomy and bilateral oo-phorectomy [5]. Surgery can be performed as a two-stage op-eration with separate resections of the intracardiac tumor and the abdominopelvic tumor, or as a one-stage operation with total resection of the entire tumor [7]. The recurrence rate af-ter resection is 30%. Therefore, surveillance imaging every few months may be useful to assess for recurrent disease [5, 7].


imaging findings and clinical characteristics of intravenous leiomyomatosis.

ConclusionIntravenous leiomyomatosis is a rare growth pattern of

uterine leiomyomata in which the histologically benign uter-

ine tumors grow into and extend up the draining veins. When an inferior vena caval or right atrial mass is discovered in a woman with a history of hysterectomy for uterine leiomyo-mata or who currently has uterine leiomyomata, the possibil-ity of intravenous leiomyomatosis should be considered. Im-aging should be directed toward assessing the full extent of the tumor and showing the connection between the intrave-nous tumor and the leiomyomatous uterus.

References1. Kaufman LB, Yueh BM, Bierman RS, Joe BN, Hayem A, Coakley FV. Inferior

vena cava filling defects on CT and MRI. AJR 2005; 185:717–726

2. Sheath S, Fishman EK. Imaging of the inferior vena cava with MDCT. AJR 2007; 189:1243–1251

3. Ueda H, Togashi K, Konica I, et al. Unusual appearances of uterine leiomyo-mas: MR imaging findings and their histopathologic backgrounds. RadioGraph-ics 1999; 19[spec no]:S131–S145

4. Cohen DT, Oliva E, Hahn PF, Fuller AF Jr, Lee SI. Uterine smooth-muscle tu-mors with unusual growth patterns: imaging with pathologic correlation. AJR 2007; 188:246–255

5. Ahmed M, Zangos S, Reichstein WO, Vogel TJ. Tips and tricks: intravenous leiomyomatosis. Eur Radiol 2004; 14:1316–1317

6. Vari G, Carazzi S, Bussichella F, et al. Intravenous leiomyomatosis extending from the inferior caval vein to the pulmonary artery. J Thorac Cardiovasc Surg 2007; 133:831–832

7. Fang BR, Ng YT, Yeh CH. Intravenous leiomyomatosis with extension to the heart: echocardiographic features—a case report. Angiology 2007; 58:376–379




AJR Teaching File: Asymptomatic Man with Giant Negative T Waves on ECGAnil Attili1, Gisela C. Mueller1, Sharlene M. Day2

Keywords: hypertrophic cardiomyopathy, MRI

DOI:10.2214/AJR.07.7116

Received July 31, 2008; accepted without revision August 12, 2008.1Department of Radiology, Division of Cardiothoracic Radiology, East Ann Arbor Health and Geriatrics Center, University of Michigan, 4260 Plymouth Rd., Rm. 1847 SPC 2713, Ann Arbor, MI 48109-2713. Address correspondence to A. Attili ([email protected]).2Department of Internal Medicine, Division of Cardiovascular Medicine, University of Michigan Medical Center, Ann Arbor, MI.


Case HistoryA 40-year-old asymptomatic man presents for a routine

health maintenance examination. The physical examina-tion is normal; in particular, he is normotensive. ECG re-veals diffuse deep T wave inversion. His family history is significant for unexplained sudden cardiac death in his fa-ther. MRI was performed to further evaluate an abnormal-ity revealed on echocardiography.

Radiologic DescriptionCine bright blood MR images of the heart (Figs. 1A–1F)

obtained with a balanced steady-state free precession tech-nique show thickened myocardium extending from the mid-ventricular to the apical regions of the left ventricle (LV). The LV septum and lateral wall have a maximum end dia-stolic thickness of 23 mm (Figs. 1E and 1F). The basal re-gions of the myocardium, including the basal septum, are unaffected, and no obstruction of the outflow tract is seen (Figs. 1C and 1D). The ventricular cavity has a spadelike configuration, with the extreme apical region being spared. Review of cine images (Fig. S1) shows the extreme apical segment to be akinetic. (Supplemental video in three-cham-ber plane, Fig. S1, is available in supplemental data at www.ajronline.org.) A delayed contrast-enhanced image shows enhancement of the thickened myocardium at the apex of the LV extending to the anterior and inferior walls in a non-coronary-artery distribution sparing the subendocardium (Figs. 1G and 1H).

DiagnosisThe diagnosis is apical hypertrophic cardiomyopathy.

CommentaryHypertrophic cardiomyopathy (HCM) is a relatively

common form of genetic heart disease, having an incidence of 1:500 in the general population, and is the most frequent cause of sudden cardiac death in the young [1]. Familial clustering is often observed; the disease is transmitted as a

Mendelian autosomal dominant trait with variable pene-trance due to heterogeneous mutations involving any one of 10 genes encoding for myocardial sarcomere proteins. The characteristic feature is an inappropriate myocardial hypertrophy in the absence of an obvious cause such as sys-temic hypertension or aortic stenosis. Histologically, HCM is characterized by disorganization and malalignment of the myofibrils (i.e., myofibrillar disarray) and abnormal in-tramural coronary arteries characterized by thickened walls with increased intimal and medial collagen and narrowed

lumen. Such architectural alterations of the microvascula-ture, as well as the mismatch between myocardial mass and coronary circulation, are likely responsible for the impaired coronary vasodilator reserve and bursts of myocardial isch-emia that lead to myocyte death and repair in the form of patchy or transmural replacement scarring.

Different morphologic types of HCM exist [2]. In most patients, the ventricular septum and the anterior LV wall are preferentially involved, with abnormalities most promi-nent in the basal segments (asymmetrical septal hypertro-phy). The LV end-diastolic septal thickness is typically greater than 15 mm. During systole, deformation and bulg-ing of the hypertrophied septum into the left ventricular outflow tract (LVOT) produce flow acceleration and a pres-sure drop across the LVOT. Anterior movement and even-tual apposition of the anterior mitral valve leaflet to the septum may occur (systolic anterior motion phenomenon), further contributing to the dynamic LVOT obstruction. Secondary mitral regurgitation is often observed. Other less frequent forms of HCM include the apical form, midven-tricular hypertrophy, and concentric LV hypertrophy pat-terns [2].

Apical HCM is a relatively rare form of HCM that was first described in Japan, where it represents 13–25% of the entire HCM population. Outside Japan, apical HCM is less common and has been reported in 3–11% of all HCM pa-tients [3]. The typical features of apical HCM consist of gi-ant T wave negativity on the ECG and hypertrophy confined

Attili et al.


A

C

Fig. 1—40-year-old man with giant negative T waves on ECG. See also Figure S1 in supplemental data at www.ajronline.org.A and B, Four-chamber images of heart in diastole (A) and systole (B) using balanced steady-state free precession (SSFP) MRI technique. Note thickening confined to apical portions of left ventricle, producing spadelike left ventricular cavity.C and D, Left ventricular outflow tract images in diastole (C) and systole (D) using balanced SSFP MRI technique show thickening of apical regions of left ventricular myocardium and sparing of basal region. There is no obstruction of left ventricular outflow tract.


B

D


Negative T Waves on ECG

ognized complication of apical HCM [6]. Various degrees of abnormal apical segments may occur, ranging from a large apical aneurysm requiring surgical removal to apical hy-pokinesis [3].

Clinically, HCM requires an accurate diagnosis, determi-nation of the distribution of hypertrophy and its functional consequences, and assessment of the likelihood of sudden death and progression to heart failure.

Two-dimensional and Doppler echocardiography are the most commonly used noninvasive methods for studying

to the distal portions of the LV wall, producing a spadelike configuration of the LV cavity [4, 5]. These patients have no LVOT obstruction. Apical HCM is not associated with sudden cardiac death and has a relatively benign prognosis in terms of cardiovascular mortality [3]. However, one third of patients with apical HCM may develop unfavorable clin-ical events and potentially life-threatening morbid compli-cations, such as apical myocardial infarction, arrhythmias, and stroke. Apical myocardial infarction and aneurysm for-mation in the presence of normal coronary arteries is a rec-

E

G

Fig. 1 (continued)—40-year-old man with giant negative T waves on ECG.E and F, Short-axis images through apex of left ventricle in diastole (E) and systole (F) using balanced SSFP MRI technique show left ventricular septum and lateral wall have maximum end-diastolic thickness of 23 mm. Cavity of left ventricle is obliterated in systole.G and H, Delayed myocardial enhancement images in four-chamber plane show enhancement of thickened myocardium at apex. Enhancement involves both anterior and inferior walls and is not in distribution of a single epicardial coronary artery. Subendocardial region is spared.

F

H

Attili et al.


HCM. However, the 3D nature of cardiac MRI allows pre-cise definition of the site and extent of hypertrophy and has been shown to be more accurate than echocardiography for determining regional hypertrophy and identifying the different phenotype forms. In particular, the apical form of HCM may be undetected on echocardiography because of near-field problems with the echo probe [7, 8]. Cardiac MRI can identify regions of LV hypertrophy not readily recog-nized by echocardiography and may be solely responsible for the diagnosis of the HCM phenotype in an important minority of patients. Cardiac MRI enhances the assessment

of LV hypertrophy, particularly in the anterolateral LV free wall and apex, and is a powerful supplemental imaging test with distinct diagnostic advantages for selected HCM patients. Particularly in patients in whom echocardio-graphy is technically unsatisfactory, cardiac MRI should be considered the technique of choice for diagnosing and fol-lowing up patients with all variants of HCM [9].

Cardiac function and flow dynamics at the LVOT in the event of LVOT obstruction are also well characterized by cardiac MRI. The turbulent jet across the LVOT during sys-tole is easily detected by cine MRI, and gradients across the LVOT can be quantified using velocity-encoded techniques. The systolic anterior motion of the anterior mitral valve, a feature of the obstructive form of HCM, is readily detectable by cardiac MRI, and any consequent mitral regurgitation can be quantified. Cardiac MRI tagging may be used to iden-tify abnormal patterns of strain, shear, and torsion in HCM, showing significant dysfunction in hypertrophic areas [10].

More recently, late-enhancement gadolinium cardiac MRI has been used in HCM to show areas of fibrosis [11–13]. Enhancement was invariably found in hypertrophied re-gions, with the pattern being patchy and multiple foci pre-dominantly involving the middle third of the ventricular wall and the junction of the ventricular septum and right ventricular free wall. The extent of enhancement was posi-tively correlated with wall thickness and inversely corre-lated with systolic wall thickening in the hypertrophied re-gions. Preliminary data in a selected group of patients suggest that a correlation exists between the extent of en-hancement detected by cardiac MRI and the clinical risk factors for sudden death, LV dilatation, and heart failure in HCM patients [13]. In a more recent study of a large HCM cohort with no or only mild symptoms, myocardial fibrosis detected by cardiac MRI was associated with a greater like-lihood and increased frequency of ventricular tachyar-rhythmias on ambulatory ECG using a Holter monitor [14]. Identifying patients at high and low risk is an important but problematic aspect of the clinical management of HCM, particularly with the availability of an effective but not hazard-free treatment option, the implantable cardio-verter-defibrillator.

Treatment strategies depend on appropriate patient se-lection, including drug treatment for exertional dyspnea

(β-blockers, verapamil, disopyramide) and the septal myo-tomy–myectomy operation, which is the standard of care for severe refractory symptoms associated with marked outflow obstruction; alcohol septal ablation and pacing are alternatives to surgery for selected patients [1]. Sudden car-diac death is the most dreaded complication and is most common in adolescents and young adults who are often asymp tomatic. The currently recognized major risk factors for sudden cardiac death in HCM include unexplained syn-cope (particularly when exertional or recurrent), a family history of HCM-related sudden death, identification of high-risk mutant genes, frequent multiple or prolonged epi-sodes of nonsustained ventricular tachycardia on Holter monitoring, abnormal blood pressure response to exercise, and extreme degrees of LV hypertrophy (maximum LV wall thickness ≥ 30 mm) [15]. Risk stratification for sudden cardiac death is of critical importance, and high-risk pa-tients may be treated effectively for sudden death preven-tion with placement of an ICD [16].


MRI features of apical HCM and to discuss the usefulness of MRI in the diagnosis of HCM.

ConclusionApical HCM is a relatively rare form of HCM character-

ized by deep negative T waves on ECG, hypertrophy involv-ing the apical regions of the heart not associated with LVOT obstruction, and a relatively benign prognosis in terms of cardiovascular mortality. Cardiac MRI allows pre-cise definition of the site and extent of hypertrophy in HCM and is more accurate than echocardiography for de-termining regional hypertrophy and identifying different phenotypes such as the apical form of HCM, which may be undetected on echocardiography. Preliminary data have shown that MRI delayed hyperenhancement in HCM is as-sociated with markers of sudden cardiac death and progres-sive disease, with possible additional prognostic informa-tion for risk stratification.

References 1. Maron BJ. Hypertrophic cardiomyopathy: a systematic review. JAMA 2002;

287:1308–1320

2. Wigle ED. Cardiomyopathy: the diagnosis of hypertrophic cardiomyopathy. Heart 2001; 86:709–714

3. Eriksson MJ, Sonnenberg B, Woo A, et al. Long-term outcome in patients with apical hypertrophic cardiomyopathy. J Am Coll Cardiol 2002; 39:638–645

4. Sakamoto T, Tei C, Murayama M, Ichiyasu H, Hada Y. Giant T wave inversion as a manifestation of asymmetrical apical hypertrophy (AAH) of the left ven-tricle: echocardiographic and ultrasono-cardiotomographic study. Jpn Heart J 1976; 17:611–629

5. Yamaguchi H, Ishimura T, Nishiyama S, et al. Hypertrophic nonobstructive cardiomyopathy with giant negative T waves (apical hypertrophy): ventriculo-graphic and echocardiographic features in 30 patients. Am J Cardiol 1979; 44:401–412

6. Matsubara K, Nakamura T, Kuribayashi T, Azuma A, Nakagawa M. Sustained


Negative T Waves on ECG

cavity obliteration and apical aneurysm formation in apical hypertrophic cardiomyopathy. J Am Coll Cardiol 2003; 42:288–295

7. Moon JC, Fisher NG, McKenna WJ, Pennell DJ. Detection of apical hypertro-phic cardiomyopathy by cardiovascular magnetic resonance in patients with non-diagnostic echocardiography. Heart 2004; 90:645–649

8. Rickers C, Wilke NM, Jerosch-Herold M, et al. Utility of cardiac magnetic resonance imaging in the diagnosis of hypertrophic cardiomyopathy. Circula-tion 2005; 112:855–861

9. Pennell DJ, Sechtem UP, Higgins CB, et al. Clinical indications for cardiovas-cular magnetic resonance (CMR): Consensus Panel report. Eur Heart J 2004; 25:1940–1965

10. Dong SJ, MacGregor JH, Crawley AP, et al. Left ventricular wall thickness and regional systolic function in patients with hypertrophic cardiomyopathy: a three-dimensional tagged magnetic resonance imaging study. Circulation 1994; 90:1200–1209

11. Bogaert J, Goldstein M, Tannouri F, Golzarian J, Dymarkowski S. Late myo-cardial enhancement in hypertrophic cardiomyopathy with contrast-enhanced

MR imaging. AJR 2003; 180:981–985

12. Choudhury L, Mahrholdt H, Wagner A, et al. Myocardial scarring in asymp-tomatic or mildly symptomatic patients with hypertrophic cardiomyopathy. J Am Coll Cardiol 2002; 40:2156–2164

13. Moon JC, McKenna WJ, McCrohon JA, Elliott PM, Smith GC, Pennell DJ. Toward clinical risk assessment in hypertrophic cardiomyopathy with gado-linium cardiovascular magnetic resonance. J Am Coll Cardiol 2003; 41:1561–1567

14. Adabag AS, Maron BJ, Appelbaum E, et al. Occurrence and frequency of ar-rhythmia in hypertrophic cardiomyopathy in relation to delayed enhancement on cardiovascular magnetic resonance. J Am Coll Cardiol 2008; 51:1369–1374

15. Elliott PM, Poloniecki J, Dickie S, et al. Sudden death in hypertrophic cardio-myopathy: identification of high risk patients. J Am Coll Cardiol 2000; 36:2212–2218

16. Maron BJ, Shen WK, Link MS, et al. Efficacy of implantable cardioverter–defibrillators for the prevention of sudden death in patients with hypertrophic cardiomyopathy. N Engl J Med 2000; 342:365–373

F O R Y O U R I N F O R M A T I O N

A data supplement for this article can be viewed in the online version of the article at: www.ajronline.org.


Erratum

Postmenopausal bleeding and premenopausalbleeding unresponsive to hormonal or medical therapy

Endovaginal ultrasound

Normal endometrium< 5 mm postmenopausal< 16 mm premenopausal

Abnormal endometriumabnormal thickness or morphology

Focal lesion workup Endometrial biopsy

MalignantBenign Inadequate sample

Cancer surgery

*Age > 35 years old, morbid obesity, chronic diabetes or hypertension, chronic tamoxifen exposure.

Repeat endometrialbiopsy or D&C

Premenopausal bleeding withhigh risk for endometrial cancer*

Sonohysterography

Focal lesion No focal lesion

Hysteroscopic resection Endometrial biopsy orD&C if bleeding persists

Author Corrections

In the article titled “Radiological Reasoning: Algorithmic Workup of Abnormal Vaginal Bleeding with Endovaginal Sonography and Sonohysterography,” which appeared in the December 2008 issue of AJR Integrative Imaging (AJR 2008; 191[suppl]:S68–S73), the criteria for normal endometrial thickness reported in the algorithm in Figure 3 was inaccurate. The corrected algorithm appears here.

We sincerely regret this error.

Ann A. ShiMontefiore Medical Center

Bronx, NYSusanna I. Lee

Massachusetts General HospitalBoston, MA

Fig. 3—Algorithm for evaluating women with abnormal vaginal bleeding. In asymptomatic postmenopausal women, endometrial thickness of > 6 mm (for patients not undergoing hormone replacement therapy) or > 8 mm (for those receiving hormone replacement therapy) is considered abnormal and should trigger a similar workup for endometrial abnormalities [24]. Threshold for workup of asymptomatic women taking tamoxifen is controversial, with endometrial thickness cutoffs of 5–8 mm having been proposed. D&C = dilatation and curettage.

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