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Fragmentation of an Intracerebral Embolus After IV Tissue Plasminogen Activator Treatment

A 49-year-old man was admitted to thehospital for evaluation of right lower extrem-ity claudication. He had no history of cere-brovascular disease, and findings of theneurologic examination were normal. Ap-proximately 2 hr after undergoing aortic archaortography, the patient developed a sudden

neurologic deficit, and at examination wasfound to have a global aphasia with mildright-sided weakness in his face and arm.The patient’s vital signs were stable. A brainCT scan obtained 1 hr later showed an areaof low attenuation in the left insular cortex aswell as a calcific plaque or clot in the leftmiddle cerebral artery M1 segment (Fig.1A). Brain infarction was diagnosed. IV tis-sue plasminogen activator was administered

according to the National Institute of Neuro-logical Disorders and Stroke protocol [1]within 2 hr of onset of symptoms.

A follow-up brain CT scan obtained 20 hrafter onset of stroke symptoms revealed frag-mentation of the original plaque or clot intoat least two smaller emboli with distal migra-tion (Figs. 1C and 1D). There was also hem-orrhagic transformation of the infarcted area(Figs. 1B and 1C). Further examination ofthe patient on angiography showed neitherstenosis nor occlusion of the left middle ce-rebral artery M1 segment. A 60% stenosis ofthe left internal carotid artery origin was de-tected. The neurologic deficit improved dur-ing the subsequent days with a gradualrecovery of speech and a complete resolutionof the weakness. At discharge, the patientwas taking only aspirin.

Emboli that occlude intracranial arteriesand cause brain ischemia are usually difficultto monitor clinically in patients. Follow-upangiographic studies suggest acute occlu-sions of the principal brain arteries spontane-ously resolve within days after the onset ofsymptoms. Pathologic examination of thebrain, which often takes place weeks afterthe stroke, can show occlusions of distal arte-rioles. Clot lysis and arterial patency can berevealed on angiography during intraarterialthrombolysis [2]. A favorable prognosis isassociated with early reestablishment of flowto the ischemic brain.

Our patient is an example of a case ofearly fragmentation and distal migration ofan embolus. These events occurred in associ-ation with IV tissue plasminogen activatoradministration and subsequent gradual im-provement of the neurologic deficit. Thesebrain CT findings may be of interest to phy-sicians caring for patients with acute stroke.

Mihran Artinian

Harvard Medical SchoolBoston, MA 02115

Viken Babikian

Boston University School of MedicineBoston, MA 02118-2526

References

1. National Institute of Neurological Disorders andStroke rt-PA Stroke Study Group. Tissueplasminogen activator for acute ischemic stroke.

N Engl J Med

1995

;333:1581–15872. del Zoppo GJ, Higashida RT, Furlan AJ, Pessin

MS, Rowley HA, Gent M. PROACT: a phase IIrandomized trial of recombinant pro-urokinaseby direct arterial delivery in acute middle cerebralartery stroke.

Stroke

1998

;29:4–11

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Fig. 1.—49-year-old man with global aphasia and sudden onset of right arm and facial weakness.A, Unenhanced brain CT scan obtained 1 hr after onset of stroke symptoms shows calcific plaque or clot (arrow)in left middle cerebral artery distal M1 segment. No other emboli are seen in middle cerebral artery branches. B, Follow-up unenhanced CT scan obtained 20 hr after onset of stroke more clearly shows low-attenuation areain left frontal and insular cortex.C and D, Unenhanced brain CT scans show evidence of hemorrhagic transformation. M1 segment embolus is nolonger visible, but its fragments can now be seen in operculofrontal (arrow, C) and insular (arrow, D) branches ofmiddle cerebral artery.

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Gadolinium Diffusion into Subdural Space: Visualization with FLAIR MR Imaging

We read with interest the article entitled “Sub-arachnoid Gadolinium Enhancement Mimick-ing Subarachnoid Hemorrhage on FLAIR MRImages” by Lev and Schafer [1], which dealtwith the leakage of contrast material into thesubarachnoid space detected on fluid-attenuatedinversion recovery (FLAIR) MR imaging. Wereport our observation of gadolinium leakageinto the subdural space detected on FLAIR MRimages in patients with subdural hemorrhage.

FLAIR MR imaging is an inversion recoverypulse sequence that produces a cerebrospinalfluid–nulled heavily T2-weighted image. Also,FLAIR has mild T1-weighting, so paramag-netic contrast material appears hyperintense.

Prompt identification of subdural hemorrhageis important for proper treatment of patients. Al-though a large acute subdural hemorrhage can be

recognized on FLAIR or conventional T1- andT2-weighted MR images, a smaller or thinner(usually <3–4 mm) hemorrhage could be missedbecause the blood is isointense to the adjacentbrain parenchyma or skull (Fig. 2A).

Two patients with acute (< 48 hr durationand containing oxyhemoglobin) and five pa-tients with chronic (>14 days duration) subdu-ral hemorrhage were examined. The chronicsubural hemorrhage appeared isointense to thecerebrospinal fluid on the unenhanced T1- andT2-weighted sequences.

After administering astandard dose of 0.1 mmol per kg of bodyweight of IV gadolinium, we first obtained T1-weighted images and then fast-FLAIR images.

FLAIR MR images obtained with gadolin-ium revealed a characteristic intense dural andsubdural enhancement in all seven patients withsubdural hemorrhage, both acute and chronic(Figs. 2B and 3B). In addition, the extent of theacute subdural hemorrhage was best visualized

on gadolinium FLAIR images compared withthe conventional T1- or T2-weighted or unen-hanced FLAIR images. Gadolinium-enhancedT1-weighted spin-echo images showed duralenhancement in one of the patients with acutehemorrhage and in all of the patients withchronic hemorrhage (Fig. 3A); however, the en-hancement was much more intense on the gado-linium-enhanced FLAIR images.

The increased conspicuity of subdural hem-orrhage on the gadolinium FLAIR images ap-pears to be related to the diffusion of contrastmaterial into the subdural space. The diffusionof gadolinium is likely due to the increasedmembrane permeability and neovascularizationrelated to trauma and associated inflammation.The mechanism for better visualization of gado-linium-induced hyperintensity on FLAIR MRimages is probably related to a combination ofthe presence of a lower concentration of gado-linium within the subdural space because of the

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Fig. 2.—60-year-old man with trau-matic acute subdural hemorrhage.A, Unenhanced fluid-attenuated in-version recovery (FLAIR) MR imageshows no definite evidence of sub-dural fluid collection. B, Gadolinium-enhanced FLAIR MRimage clearly shows presence andactual extent of subdural hemor-rhage within posterior fossa.

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Fig. 3.—61-year-old man who had fallen 2 months earlier.A, Gadolinium-enhanced T1-weighted MR image re-veals diffuse bilateral dural enhancement.B, Gadolinium-enhanced fluid-attenuated inversionrecovery (FLAIR) MR image shows diffuse dural andsubdural enhancement, presumably related to diffu-sion of contrast medium into subdural space.

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diluting effect of blood and the effect of T1-weighting on the FLAIR images [2].

For the larger clinically significant subduralhemorrhage in adults, the conventional T1- and T2-weighted MR sequences are probably adequate;however, when the subdural hemorrhage is smalland thin, gadolinium-enhanced FLAIR MR imag-ing appears to be the best sequence for detectionand visualization of the full extent of the subduralhemorrhage. This finding could be important inproper treatment of infants and children in whomthin (3–4 mm) subdural hemorrhage could be clini-cally significant [3]. Similarly, subdural hemor-rhage in the posterior fossa often tends to be thinand would probably be best revealed by gadolin-ium-enhanced FLAIR MR imaging. Lastly, we be-lieve that there is a role for gadolinium-enhancedFLAIR MR imaging in the assessment of sus-

pected intracranial injury caused by child abuse;subdural hemorrhage is the most frequent form ofintracranial abnormality found in these patients.

Uday S. KanamallaKim B. Baker

Orest B. Boyko

Temple University HospitalPhiladelphia, PA 19140

References

1. Lev MH, Schafer PW. Subarachnoid gadoliniumenhancement mimicking subarachnoid hemorrhageon FLAIR MR images: fluid-attenuated inversionrecovery.

AJR

1999

;173:1414–14152. Mathews VP, Caldmeyer KS, Lowe MJ, Greenspan

SL, Weber DM, Ulmer JL. Brain: gadolinium-enhanced fast fluid-attenuated inversion recoveryMR imaging.

Radiology

1999

;211:257–2633. Stehbens WE.

Subdural hematoma: pathology of cere-bral blood vessels

. St. Louis: Mosby,

1972

:224–250

Scrotal Sonography for Assisting in Testis-Sparing Surgery in a Prepubertal Boy

In children, cystic lesions in the testes are rareand represent an interesting group of diagnoses.The lesions are categorized by patient age at pre-sentation, findings at physical examination andon scrotal sonography, and tumor markers, all ofwhich may assist physicians in making a preop-erative diagnosis. Enucleation or partial orchiec-tomy with frozen-section histologic assessmentmay be considered. We describe the commonyet previously unreported use of intraoperativesonographic testicular imaging for assistancein testis-sparing surgery. In addition, to ourknowldge, our patient is the first reported case ofbilateral and multiple testicular epidermoid cysts.

A left testicular nodule was found inciden-tally at physical examination of a 7-year-old

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Fig. 4.—7-year-old boy with multiple and bilateral tes-ticular epidermoid cysts.A, Longitudinal sonogram of left scrotum reveals well-defined 5-mm echogenic mass surrounded by hypo-echoic rim (arrows). Increased through-transmissionsuggests cystic mass.B, Longitudinal sonogram of right scrotum reveals twomasses: 5-mm echogenic mass (solid arrow) with hy-poechoic rim in lower pole and 3-mm hypoechoic mass(open arrow) in upper pole.C, Photograph of three enucleated lesions from bothtestes.

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boy. The patient’s history, preoperative labora-tory results, and findings at physical examina-tion and on chest radiographs were all normal.Scrotal sonography revealed a left 5-mm intra-testicular mass and, in addition, two previouslyunsuspected right intratesticular masses mea-suring 5 and 3 mm, respectively. All werecomplex echogenic masses with increasedthrough-transmission (Figs. 4A and 4B). In-guinal exploration of both testes revealed twowhitish yellow masses on the outer surface, onebulging from the left testicle and the other at thelower pole of the right testis. Both masses wereshelled out. Assisted by direct intraoperativesonographic imaging, we detected an additionalmass measuring 3

×

4 mm deep within the righttesticular parenchyma, which was also enucle-ated. The final pathology findings were that allthree lesions were epidermoid cysts (Fig. 4C).

Epidermoid cysts are benign cystic testiculartumors inside the parenchyma of the testis. Theyusually occur during the third decade of life andare uncommon in children, accounting for only3% of all testicular tumors in the pediatric popu-lation. Of the approximately 200 patients withtesticular epidermoid cysts reported in the litera-ture, only five had bilateral involvement [1]. Toour knowledge, our patient is the first reportedcase of multiple and bilateral epidermoid cysts.

In our patient, sonography served three pur-poses. First, it revealed two additional massesunsuspected at physical examination; second,it was useful in showing that the lesions werewell circumscribed and had the characteristicsof epidermoid cysts [2]; and third, it helped us

intraoperatively to accurately locate and dis-sect the deeply situated small epidermoid cyst,thereby preventing unnecessary damage tohealthy testicular tissue.

Urologists and radiologists should be awareof the benefit of intraoperative sonographicimaging in testis-sparing surgery, especially incases of small deeply situated masses.

Ofer YossepowitchBoaz Karmazin

Pinhas M. Livne

Schneider Children’s Medical Centerof Israel

Tel Aviv UniversityTel Aviv, 61390 Israel

References

1. Neumann DP, Abrams GS, Hight DW. Testicularepidermoid cysts in prepubertal children: casereport and review of the world literature.

J Pedi-atr Surg

1997

;32:1786–17892. Maxwell AJ, Mamtora H. Sonographic appear-

ance of epidermoid cyst of the testis.

J Clin Ultra-sound

1990

;1:188–190

The Aortic Sling: Malpositioned Aortic Arch Surrounding and Compressing the Trachea in a Patient with Thoracic Deformity

Extrinsic compression of the trachea andcentral airways is one of more common dis-eases of the central airways in children, andvascular rings such as the double aortic arch,other arch anomalies, and anomalous origin ofthe left pulmonary artery are among the best-known vascular causes of tracheal compres-

sion [1]. However, there are a number of othervascular causes of airway compression in chil-dren that are not as well known and, yet, arenot rare occurrences [2]. Because of the con-fined space of the superior mediastinum, al-most any abnormally enlarged structure,malpositioned structure, or mediastinal masshas the potential to cause airway obstruction[2]. In many tertiary centers, to which childrenwith multiple medical problems are frequentlyreferred, these other causes of airway com-pression may be encountered at rates similar tothose of the classic vascular rings. The morecommon of these other causes of airway com-pression include an enlarged ascending aorta,malpositioned descending aorta, enlarged pul-monary arteries, enlarged left atrium, nonvas-cular mediastinal masses, and abnormalities ofchest wall configuration [2, 3].

Of the well-described vascular rings,anomalous origin of the left pulmonary ar-tery (pulmonary sling) is the only true“sling.” In patients with this condition, theleft pulmonary artery arises from the rightpulmonary artery rather than from the typicalpoint of origin, off the main pulmonary ar-tery [1]. The abnormal origin leads to the leftpulmonary artery wrapping around the tra-chea as it courses leftward toward the lefthemithorax and passes between the tracheaand esophagus [1]. This pulmonary sling re-sults in compression of the distal trachea.

We recently encountered a patient in whoman “aortic sling” was the cause of tracheal com-pression. A 19-year-old woman with multiple

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Fig. 5.—Thoracic deformity leading to airway compression in 19-year-old woman with severe scoliosis.A, Frontal chest radiograph shows severe scoliosis resulting in thoracic deformity. Right hemithorax is asymmetrically small and shifted superiorly compared with left.There are spinal rods in place.B, CT scan reveals severe deformity of thorax with small right hemithorax and vertebral bodies oriented toward right, resulting in descending aorta (D) being positioned extremelyrightward and superior. As a result, ascending aorta (A) and aortic arch are oriented in axial plane and form sling around trachea (arrow), leading to its compression.

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medical problems, including severe scoliosisand a posterior thoracic mixed vascular mal-formation, was examined using a contrast-en-hanced CT scan of the chest obtained becauseof stridor that had been refractory to medicaltherapy. The scoliosis had resulted in severethoracic deformity with a small right andlarger left hemithorax (Fig. 5A). The CT scanrevealed that the patient’s severe thoracic de-formity had resulted in the descending aortabeing positioned much more rightward andsuperior than normal (Fig. 5B). The abnormalposition of the descending aorta resulted inthe aortic arch being oriented in the axialplane in a

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-shaped sling (Fig. 5B). The aor-tic sling surrounded and compressed the tra-chea. The esophagus was in a posterior andrightward location, not within the confines ofthe aortic sling.

Tracheal compression as a result of abnor-mal thoracic configuration has been previouslyreported [2–4]. Abnormal thoracic configura-tion can be associated with a narrow antero-posterior chest diameter that results in directcompression of the trachea between the manu-brium and spine at the level of the thoracic in-let [3]. Also, abnormal thoracic configurationcan lead to an alteration in the anatomic rela-tionship between the airway and adjacentstructures resulting in abnormal anterior toposterior “stacking” of mediastinal structuresand resultant tracheal compression. Thismechanism usually results in compression ofthe proximal left main bronchus [3, 4]. In thispatient, the altered position of the descendingaorta and orientation of the aortic arch resultedin an aortic sling that compressed the mid tra-chea. I have not previously encountered such a

case. Aortic sling should be considered in thedifferential diagnosis of tracheal compressionoccurring in patients with thoracic deformity.

Lane F. Donnelly

Children’s Hospital Medical CenterCincinnati, OH 45229-3039

References

1. Berdon WE, Baker DH. Vascular anomalies andthe infant lung: rings, slings, and other things.

Semin Roentgenol

1972

;7:39–632. Donnelly LF, Strife JL, Bisset GS III. The spec-

trum of extrinsic lower airway compression inchildren: MR imaging.

AJR

1997

;168:59–623. Donnelly LF, Bisset GS III. Airway compression

in children with abnormal thoracic configuration.

Radiology

1998

;206:323–3264. Donnelly LF, Frush DP. Abnormalities of the chest

wall in pediatric patients.

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;173:1595–1601