diagnosing appendicitis with imaging

Plain film from www.learningradiology.com

Diagnosing Appendicitis

Heather Burns Gunn, HMS IIIGillian Lieberman, MD

Radiology CoreBIDMC

November 2007

CT, US, MRI all PACS BIDMC

with Imaging

in the Emergency Department

Let’s meet our patient in the emergency room

Patient CH: History

24 yo womanpresents to ED with 2 days of abdominal paininitially diffuse, crampy pain in epigastric areapain migrated to RLQ 12 hours ago and became sharperseveral episodes of N/V in last 12 hoursdenies diarrhea, constipation, melena, BRBPRendorses reduced appetite

Patient CH: Physical Exam & Labs

Physical exam normal except abdominal exam

Soft, non-distended, tender RLQNo rebound tenderness+ Rovsing’s sign (pain in RLQ during palpation of LLQ)

Labs of note:WBC: 16.6 with 83% NeutrophilsCreatinine: 0.9

DDx

of RLQ pain

•

GI–

Appendicitis–

Crohn’s–

Right sided diverticulitis–

Mesenteric adenitis–

Epiploic

appendagitis–

Bowel ischemia–

Right colonic neoplasia–

Infectious ileocolitis–

Mucocele

of the appendix–

Typhilitis–

Sigmoid diverticulitis–

Intussusception–

Pseudomembraneous

or cytomegalovirus colitis

–

Perforated peptic ulcer–

Perforated cholecystitis–

Pancreatitis

•

Renal–

Acute pyelonephritis–

Renal and urinary tract obstruction

•

Gynecological–

Pelvic inflammatory disease–

Hemorrhagic ovarian cyst–

Ovarian vein thrombosis–

Ovarian dermoid–

Necrotic uterine leiomyoma–

Ovarian torsion–

Endometriosis–

Ruptured ectopic pregnancy

Yu J et al. Helical CT evaluation of acute right lower quadrant pain. AJR 2005.

•

COMMONAppendicitis is the most common cause of acute abdomen.1

•

EXPENSIVE: In 2004, 300,000 cases in US alone, total healthcare cost of 5.8 billion.2

•

DANGEROUS: Before universal acceptance of appendectomy as standard of care, mortality for appendicitis was more than 50%.3

http://history1900s.about.com/library/photos/blywwiip251.htm

1Davies G et al. The burden of appendicitis related hospitalizations in the United States in 1997. Surg

Infect 2004.

2 Otero H et al. Imaging utilization in the management of appendicitis and its impacton

hospital charges. Emerg

Radiol

2007.

3

Weyant

MJ et al. Is imaging necessary for the diagnosis of acute appendicitis? Adv Surg

2003.

Before 1997, because of appendicitis’ high mortality rate, surgeons agreed that a 20% negative appendectomy rate was acceptable.

That is no longer the case . . .

. . . because of advances in imaging in emergency departments.

Colson M et al. High negative appendectomy rates are no longer acceptable. Am J Surg

1997.

Rhea J et al. The status of appendiceal

CT in an urban medical center 5 years after its introduction: experience with 753 patients. AJR 2005.

. . . because of advances in imaging in emergency departments.

Colson M et al. High negative appendectomy rates are no longer acceptable. Am J Surg

1997.

Rhea J et al. The status of appendiceal

CT in an urban medical center 5 years after its introduction: experience with 753 patients. AJR 2005.

PACS BIDMC

Plain film from www.learningradiology.com

Before we consider our menu of imaging tests to narrow our diagnosis . . . .What additional lab test should we order for our patient CH?

A pregnancy test!

+ A positive pregnancy test will change our imaging options.

-

A negative pregnancy test will remove ectopic pregnancy from our differential.

ACR appropriateness criteria for RLQ Pain fever, leukocytosis, and classic presentation for appendicitis in adults

Radiologic Procedure

Rating(1 = least appropriate,

9 = most appropriate) Relative Radiation Level

CT abdomen and pelvis with contrast 8 High

US abdomen RLQ graded compression 6 None

CT abdomen and pelvis without contrast 6 High

X-ray chest 5 Min

US pelvis transabdominal

and transvaginal 5 None

X-ray abdomen supine and upright 5 Low

X-ray colon barium enema double-contrast 4 Med

X-ray colon barium enema single-contrast 4 Med

MRI abdomen and pelvis 4 None

X-ray small bowel series with barium 3 Low

NUC gallium scan abdomen 3 High

NUC WBC scan abdomen pelvis 3 Med

X-ray small bowel enteroclysis 2 Med

www.acr.org

ACR appropriateness criteria for RLQ Pain fever, leukocytosis, pregnant woman

Radiologic Procedure

Rating(1 = least appropriate,

9 = most appropriate) Relative Radiation Level

US abdomen RLQ graded compression 8 None

MRI abdomen and pelvis 7 None

US pelvis transabdominal

and transvaginal 6 None

CT abdomen and pelvis with contrast X-ray chest 6 High

CT abdomen and pelvis without contrast 5 High

X-ray chest 4 Min

X-ray abdomen supine and upright 2 Low

X-ray colon barium enema double-contrast 2 Med

X-ray small bowel enteroclysis 2 Med

X-ray colon barium enema single-contrast 2 Med

NUC WBC scan abdomen pelvis 2 Med

X-ray small bowel series with barium 2 Low

NUC gallium scan abdomen 2 High

www.acr.org

Not pregnant

1.

CT C+ abd/pelv

2.

US abd

RLQ graded compression

3.

CT C-

abd/pelv

4.

X-ray chest

5.

US pelvis transabd

& transvag

Pregnant

1.

US abd

RLQ graded compression

2.

MRI abd

and pelvis

3.

US pelvis transabd

& transvag

4.

CT C+ abd/pelv

5.

CT C-

abd/pelv

Comparison of Appropriate Tests

Pregnant Woman and Appendicitis•

COMMON: Acute appendicitis is most common surgical emergency during pregnancy.1

•

TRICKY: Clinical diagnosis can be difficult2

–

Appendix may have moved due to gravid uterus –

pain may not localize to RLQ

–

Leukocytosis

can be physiological during pregnancy

–

Nausea and vomiting common in both pregnancy and appendicitis

•

DANGEROUS: In appendicitis, fetal loss is more than 30% with ruptured appendix and 2% with unruptured

appendix.3

1 Cobben

L et al. MRI for clinically suspected appendicitis during pregnancy. AJR 2004.2,3

Birchard

K et al. MRI of acute abdominal and pelvic pain in pregnant patients. AJR 2005.

MR Abdomen –

Sagittal: PACS BIDMC

Consideration in imaging the appendix (besides whether or not patient is pregnant or a child):

Where is the appendix?

Anterior view Posterior view

Tamburrini

S et al. CT appearance of the normal appendix in adults. Eur

Radiol

2005.

Variability in the location of the appendix

Anterior view Posterior view

Tamburrini

S et al. CT appearance of the normal appendix in adults. Eur

Radiol

2005.

Variability in the location of the appendix

18%26%

Most Most common common locationslocations

Exploring the Menu of Tests

•

Plain films

•

Ultrasound

•

MRI

•

CT


••

Plain filmsPlain films

•

Ultrasound

•

MRI

•

CT

Abdominal Plain Films

•

Abdominal plain films are neither sensitive nor specific for acute appendicitis.1

•

X-ray of chest often ordered in acute abdomen

–

to check for free air under diaphragm

–

because chest disease can simulate abdominal conditions.2

•

Some radiographic signs of acute appendicitis:3

–

Appendicolith–

Scoliosis–

RLQ fluid levels–

Ileus–

Bowel wall edema

1Rao P et al. Plain abdominal radiography in clinically suspected appendicitis: diagnostic yield, resource use, and comparison with CT. American Journal of Emergency Medicine 1999.2Greene C. Indications for plain abdominal radiography in the emergency department. Annals of Emergency Medicine 1986.3Olutola PS. Plain film radiographic diagnosis of acute appendicitis: an evaluation of the signs. Can Assoc Radiol

J. 1988.

Abdominal plain film of appendicoliths

from www.learningradiology.com

Companion Patient 1: Abdominal Plain Film of Appendicitis

Supine abdominal plain filmUpright abdominal plain film

Altering position of this pediatric patient revealed two different

radiographic signs of appendicitis.

Both images from http://www.hawaii.edu/medicine/pediatrics/pemxray/v4c10.html


of Appendicitis

Companion patient 2





Scoliosis due to RLQ splinting

Appendicolith


of Appendicitis

Companion patient 2






of Appendicitis

Scoliosis due to RLQ splinting

Appendicolith

Companion patient 2


•

Plain films √

••

UltrasoundUltrasound

•

MRI

•

CT

Ultrasound•

No radiation exposure –

good for pregnant women and children•

Patient need not be cooperative –

good for children•

Sensitivity for diagnosing appendicitis = 0.861

•

Specificity for diagnosing appendicitis = 0.812

•

Findings on ultrasound:3

–

Appendiceal

Findings•

Diameter of appendix ≥ 6 mm MOST SENSITIVE AND SPECIFIC FINDING•

Lack of compressibility of appendix 2ND MOST SENSITIVE AND SPECIFIC•

Intraluminal

fluid•

Doppler flow in wall–

Periappendiceal

Findings•

Inflammatory fat changes•

Cecal

wall thickening•

Periileal

lymph nodes•

Peritoneal fluid

1,2 Terasawa

T et al. Systematic review: computed tomography and ultrasonography

to detect acute appendicitis in adults and adolescents. Ann Inten

Med 2004.3

Kessler N et al. Appendicitis: evaluation of sensitivity, specificity, and predictive values of US, Doppler US, and laboratory findings. Radiology 2004.

Ultrasound of Appendicitis

Appendix diameteris larger than 6 mm

PACS BIDMC

Note how round appendix is despite compression with ultrasound transducer non-compressible appendix

Companion Patient 3

PACS BIDMC

Intraluminal

fluid Doppler flow in wall

Ultrasounds of Appendicitis

Companion Patient 4 Companion Patient 5

Why would you ever use anything else to diagnose appendicitis in pregnant women?

•

The Drawbacks to US:– Graded compression US is sometimes not

feasible because of enlarged uterus1

– Negative predictive value of nonvisualized appendix is .902

1Pedrosa I et al. MR imaging evaluation of acute appendicitis in

pregnancy. Radiology 2006.2Kessler N et al. Appendicitis: evaluation of sensitivity, specificity, and predictive values of US, Doppler US, and laboratory

findings. Radiology 2004.


•

Plain films √

•

Ultrasound √

••

MRIMRI

•

CT

MRI

•

No radiation exposure –

good for pregnant women

•


•


•

Findings on MRI:3

–

Diameter of appendix ≥ 6 mm –

Thickening of appendiceal

wall with high intensity on T2 weighted images

–

Dilated lumen filled with high intensity material on T2 weighted

images

–

Increased intensity of periappendiceal

tissue on T2 weighted images

1,2 Pedrosa

I et al. MR Imaging Evaluation of Acute Appendicitis in Pregnancy. Radiology 2006. 3

Nitta N et al. MR imaging of the normal appendix and acute appendicitis. Journal of Magnetic Resonance Imaging 2005.

MRI of appendicitis in a pregnant woman

PACS BIDMC

•

Appendix diameter ≥ 6 mm

• Dilated lumen filled with high intensity material

Companion Patient 6: MR T2 SSFSE (Single Shot Fast Spin Echo)

Coronal

PACS BIDMC

Appendix is dilated

Appendiceal

walls are thickened and high intensity

Increased intensity of periappendiceal

tissue indicating inflammatory changes

Companion Patient 7: MR T2 SSFSE (Single Shot Fast Spin Echo)

Coronal

MRI of appendicitis in a pregnant woman


•

Plain films √

•

Ultrasound √

•

MRI √

••

CT CT –

test of choice for non-pregnant adults

} for children and pregnant women

} for pregnant women

CT•

Test of choice for non-pregnant adults and adolescents•

CT is credited with drop in negative appendectomy rate from 20% to 3%1

•

Since CT provides view of entire abdomen and pelvis (unlike US),

other diagnoses may be made.

•


•


•

Findings on CT:4

–

Diameter of appendix ≥ 6 mm –

Periappendiceal

inflammatory changes•

Fat stranding•

Fluid collections•

Phlegmon•

Abscess formation

–

Wall thickness ≥ 3 mm–

Extraluminal

air–

Adjacent adenopathy–

Adjacent bowel wall thickening–

Focal cecal

wall thickening

1,2,3Rhea J et al. The status of appendiceal

CT in an urban medical center 5 years after its introduction: experience with 753 patients. AJR 2005.4Moteki T et al. New CT criterion for acute appendicitis: maximum depth of intraluminal

appendiceal

fluid. AJR 2007.

CT Coronal Reconstruction of Appendicitis: Companion Patient 8

Focal cecal

wall thickening.

Extensive fat stranding.

Dilated appendix.

PACS BIDMC

Where’s the appendix?

PACS BIDMC

Axial CT of appendicitis: Companion Patient 9

PACS BIDMC

Axial CT of appendicitis: Companion Patient 9

Dilated appendix, not filling with contrast

PACS BIDMC

Dilated appendix, not filling with contrast.

Axial CT of Appendicitis: Companion Patient 10

PACS BIDMC

Appendix not filling

with contrast


Fat stranding

Dilated appendix

PACS BIDMC


PACS BIDMC

Where is this man’s inflamed appendix?

Look for the fat stranding.


An aside: do you notice any other abnormality in this man’s pelvis?


PACS BIDMC

A kidney transplanted into the pelvis.

PACS BIDMC

CT Coronal Reconstruction of Appendicitis: Companion Patient 13

PACS BIDMC

Where’s the appendix in this coronal reconstruction?

Coronal Reconstruction CT: Companion Patient 14

That’s the appendix, but is this appendicitis?

PACS BIDMC

Appendix is filled with contrast.

Appendix diameter = 5.0 mm (less than 6.0 mm)

No periappendiceal

inflammatory changes to be seen!

Normal appendix

Coronal Reconstruction CT: Companion Patient 14

Back to our patient CH . . .

• she wasn’t pregnant

• her renal function was fine (creatinine

was 0.9)

. . . so she was given a CT scan with contrast.

PACS BIDMC

Patient CH: Axial CT


PACS BIDMC

Let’s find the appendix.


PACS BIDMC

PACS BIDMC

An elongated and dilated appendix.

Considerable fat stranding (as well as air in appendiceal

lumen)

Patient CH: Axial CTs

PACS BIDMC

An elongated and dilated appendix.

Considerable fat stranding (as well as air in appendiceal

lumen)

Diagnosis: Diagnosis: acute acute

appendicitis!appendicitis!

Patient CH: Axial CTs

We have our diagnosis but let’s look at the coronal reconstructions as well.

PACS BIDMC

Patient CH’s CT: Coronal Reconstruction


PACS BIDMC

Some individual coronal slices.


PACS BIDMC

The appendix pops in and out of plane in this slice.

Dilated appendix

Air bubble

Plenty of fat stranding

PACS BIDMC


PACS BIDMC

PACS BIDMC

Air in appendix lumen does not rule out appendicitis. Air is present in lumen of appendix in over 15% of cases of appendicitis imaged on CT.1

1Rao P et al. Appendiceal

and peri-appendiceal

air at CT: prevalence, appearance, and clinical significance. Clin

Radiol

1997.


•

The patient CH was taken to OR•

Laparoscopic appendectomy

•

Pathological findings: erythematous appendix, measuring 9.5 cm in length,

average of 1.2 cm in diameter. Dilated lumen of up to 0.8 cm containing some fecal material.

•

After removing the appendix and irrigating the abdomen, the surgeons turned the case over to a different team –

can you guess which kind?

Take another look at the CT coronal reconstruction . . . .

PACS BIDMC

Retrocecal

appendix

Right ovarian Right ovarian dermoiddermoid

cystcyst

CH’s CT: Coronal Reconstruction

•

Ob/Gyn

service felt it was not prudent to remove dermoid

at this time.

•

Patient was discharged from hospital two days later with plans for Ob/Gyn

follow

up.

Many thanks to . . . •

Gillian Lieberman, MD

•

Melissa Gerlach, MD

•

Bettina Siewert, MD

•

Anne Catherine Kim, MD

•

Rich Rana, MD

•

Andrew Hines-Peralta, MD

•

Maria Levantakis

BibliographyAmerican College of Radiology (2007) ACR appropriateness criteria. Acute right lower quadrant pain. Available at www.acr.org. Last accessed November

2007.Birchard

KR, Brown MA, Hyslop

WB, Firat

Z, Semelka

RC. MRI of acute abdominal and pelvic pain in pregnant patients. American Journal of Roentgenology

2005; 184: 452-458.

Colson M, Skinner KA, Dunnington

G. High negative appendectomy rates are no longer acceptable. American Journal of Surgery 1997; 174: 723-726.Cobben

LP, Groot

I, Haans

L, Blickman

JG, Puylaert

J. MRI for clinically suspected appendicitis during pregnancy.

American Journal of Roentgenology

2004; 183: 671-675.

Davies GM, Dasback

EJ, Teutsch

S. The burden of appendicitis related hospitalizations in the United States in 1997. Surgical Infections 2004; 5: 160-165.Greene C. Indications for plain abdominal radiography in the emergency department. Annals of Emergency Medicine 1986; 15: 257-260.Kessler N, Cyteval

C, Gallix

B, Lesnik

A, Blayac

PM, Pujol

J, Bruel

JM, Taourel

P. Appendicitis: evaluation of sensitivity, specificity, and predictive values of US, Doppler US, and laboratory findings. Radiology 2004; 230: 472-478.

Moteki

T, Horikoshi

H. New CT criterion for acute appendicitis: maximum depth of intraluminal

appendiceal

fluid. American Journal of Roentgenology

2007; 188: 1313-1319.

Nitta N, Takahashi M, Furukawa A, Murata K, Mori M, Fukushima M.

MR imaging of the normal appendix and acute appendicitis. Journal of Magnetic Resonance Imaging 2005; 21: 156-165.

Olutola

PS. Plain Film radiographic diagnosis of acute appendicitis: an evaluation of the signs. Canadian Association of Radioliogists

Journal 1988; 39: 254-6.Otero HJ, Ondategui-Parra S, Erturk

SM, Ochoa RE, Gonzalez-Beicos

A, Ros

PR. Imaging utilization in the management of appendicitis and its impact on hospital charges. Emergency Radiology 2007.

Pedrosa

I, Levine D, Eyvazzadeh

AD, Siewert

B, Ngo L, Rofsky

NM. MR Imaging Evaluation of Acute Appendicitis in Pregnancy. Radiology 2006; 238: 891-

899. Rao

PM, Rhea JT, Novellline

RA. Appendiceal

and peri-appendiceal

air at CT: prevalence, appearance, and clinical significance. Clinical Radiology 1997; 52: 750-754.

Rao

PM, Rhea JT, Rao

JA, Conn AKT. Plain abdominal radiography in clinically suspected appendicitis: diagnostic yield, resource use, and comparison with CT. American Journal of Emergency Medicine 1999; 17: 325-328.

Rhea JT, Halpern

EF, Ptak

T, Lawrason

JN, Sacknoff

R, Novelline

RA. The status of appendiceal

CT in an urban medical center 5 years after its introduction: experience with 753 patients. American Journal of Roentgenology

2005; 184: 1802-1808.Tamburrini

S, Brunetti

A, Brown M, Sirlin

CB, Casola

G. CT appearance of the normal appendix in adults. European Radiology 2005; 15: 2096-2103.Terasawa

T, Blackmore CC, Bent S, Kohlwes

RJ. Systematic review: computed tomography and ultrasonography

to detect acute appenditicitis

in adults and adolescents. Annals of Internal Medicine 2004; 141: 537-546.

Weyant

MF, Eachempati

Sr, Maluccio

MA, Barie

PS. Is imaging necessary for the diagnosis of acute appendicitis? Advances in Surgery 2003; 37: 327-345.Yu J, Fulcher

AS, Turner MA, Halvorsen

RA. Helical CT evaluation of acute right lower quadrant pain: part I, common mimics of appendicitis. American Journal of Roentgenology

2005; 184: 1136-1142.Yu J, Fulcher

AS, Turner MA, Halvorsen

RA. Helical CT evaluation of acute right lower quadrant pain: part II, uncommon mimics of appendicitis. American Journal of Roentgenology

2005; 184: 1143-1149.

Additional images from the following websites:http://history1900s.about.com/library/photos/blywwiip251.htm www.learngingradiology.comhttp://www.hawaii.edu/medicine/pediatrics/pemxray/v4c10.html

diagnosing appendicitis with imaging

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