Arabinda Pani, HMS III
Gillian Lieberman, MD
Radiologic Diagnosis of
Appendicitis
Arabinda Pani,
Harvard Medical School, Year III
Gillian Lieberman, MD
January 2005
2
Arabinda Pani, HMS III
Gillian Lieberman, MD
Overview
• Introduction: Epidemiology, Pathophysiology
• Role of Radiologic diagnosis
• Normal anatomy
• Appearance in various modalities
• Criteria for radiologic diagnosis
• Patient Case: Appendicitis in Pregnancy
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Arabinda Pani, HMS III
Gillian Lieberman, MD
Epidemiology
•Appendicitis-associated abdominal pain is a
common presentation to ED
•Peak Incidence: 10 – 30 years of age
•Lifetime incidence: 7% in United States
•Historically, high rate of false negatives and
false positives
•20% of diagnoses initially missed
•20% of appendectomies revealing a normal
appendix
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Arabinda Pani, HMS III
Gillian Lieberman, MD
Pathophysiology
• The lumen of the appendix becomes obstructed,
leading to increased intraluminal pressure
resulting in inflammation, ischemia, and infection
• Obstruction is most often secondary to:
• Appendicoliths
• Lymphoid hyperplasia
• Parasite infections
• Tumors (carcinoid, metastatic)
• Foreign bodies
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Arabinda Pani, HMS III
Gillian Lieberman, MD
Complications of Appendicitis
• Perforation
• Abscess formation
• Generalized peritonitis
• Small bowel obstruction
The rate of complications increases with time
until diagnosis and treatment.
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Arabinda Pani, HMS III
Gillian Lieberman, MD
Classic Presentation
• Dull, generalized
abdominal pain,
migrates to RLQ over
24 hours
• Nausea, Vomiting,
Anorexia
• Low-grade fever
• Abdominal tenderness
• Guarding
• Rebound tenderness
• Obturator and Psoas
Signs
• Elevated WBC
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Arabinda Pani, HMS III
Gillian Lieberman, MD
Role of Radiologic Diagnosis
• Appendicitis is highly
prevalent
• Often presents
atypically especially in
children, women and
the elderly
• Complications are
common and time-
dependent
Radiologic Diagnosis:
• Is effective in significantly
increasing diagnostic
accuracy
• Decreases morbidity and
mortality by:
•preventing complications
•avoiding unnecessary
surgeries
• Lowers the overall cost of
healthcare
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Arabinda Pani, HMS III
Gillian Lieberman, MD
Anatomy
Gray’s Anatomy
adam.com
9
Arabinda Pani, HMS III
Gillian Lieberman, MD
Normal Appendix
contrast-filled appendix on barium study contrast in appendix (CT)
http://www.emedicine.com/radio/topic47.htm
10
Arabinda Pani, HMS III
Gillian Lieberman, MD
Ultrasound: Normal Appendix
Longitudinal ultrasonography shows compressible
tubular structure with an outer diameter of less than
6 mm. A=Iliac artery; V=Iliac vein.
http://emedicine.com/radio/topic47.htm
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Arabinda Pani, HMS III
Gillian Lieberman, MD
Normal Appendix: MR
Courtesy Dr. Eric Zeikus, PACS:BIDMC
Low Signal Intensity
Non-distended
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Arabinda Pani, HMS III
Gillian Lieberman, MD
Radiologic Findings of Appendicitis
• Inflammatory changes
• Lumenal obstruction
• Appendicoliths
Plain Film
Film is normal in > 50% of
patients with appendicitis
Only 10% demonstrate a
calcified, laminated
appendicolith(s)
Other findings are non-
specific
Barium Enema
Diagnostic criteria requires
visualization of a non-
filling appendix
Often non-diagnostic with
low sensitivity
Invasive
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Arabinda Pani, HMS III
Gillian Lieberman, MD
Plain Film: Calcified Appendicolith
http://telesalud.ucaldas.edu.co
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Arabinda Pani, HMS III
Gillian Lieberman, MD
Graded Compression Ultrasound
•Blind-ended, tubular, noncompressible, aperistaltic structure
•Diameter > 6 mm, laminated wall
•Increased periappendiceal echogenicity
•Appendicolith: echogenic with distal shadowing
•Doppler: increased circumferential flow
•Perforation/Abscess: thickening of adjacent bowel wall, fluid
collections, hypoechoic mass
Overall diagnostic accuracy: 85%
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Arabinda Pani, HMS III
Gillian Lieberman, MD
Appendicitis on Ultrasound
Non-compressible, blind-ended
8mm diameter
Laminated wall
Birnbaum B A, and Wilson S R. Appendicitis at the Millennium. Radiology 2000 215: 337-348.
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Arabinda Pani, HMS III
Gillian Lieberman, MD
Color Doppler Ultrasound
Birnbaum B A, and Wilson S R. Appendicitis at the Millennium. Radiology 2000 215: 337-348.
Circumferential Flow,
suggestive of hypervascularity
and inflammation
17
Arabinda Pani, HMS III
Gillian Lieberman, MD
Appendicolith on US
Birnbaum B A, and Wilson S R. Appendicitis at the Millennium. Radiology 2000 215: 337-348.
• Bright, echogenic
focus
• Clean distal
acoustic shadowing
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Arabinda Pani, HMS III
Gillian Lieberman, MD
Perforated Appendix on US
http://lunis.lumc.edu/radiology/Appendicitis
• Perforated Appendix with Free
Peritoneal Fluid (FF) surrounding
loops of bowel (B).
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Arabinda Pani, HMS III
Gillian Lieberman, MD
CT Diagnosis
Primary Criteria:
• Enlarged, inflamed
appendix
– diameter >6 mm in
adults
– > 8mm in children
• Appendicolith
• Non-contrast filled
Secondary Criteria:
• Wall enhancement
• Fat stranding
• Abscess formation
• Focal thickening of the
cecum (arrow-head sign)
• Adenopathy
• Small bowel obstruction
• Free fluid in the pelvis
Overall Accuracy: 98%
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Arabinda Pani, HMS III
Gillian Lieberman, MD
Uncomplicated Appendicitis: CT
Courtesy of Dr. Michael Geary, PACS: BIDMC
• Non-contrast filled
• Enlarged appendix,
14 mm in diameter
• Adjacent fat stranding
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Arabinda Pani, HMS III
Gillian Lieberman, MD
Coronal CT: Enhancing Wall
PACS: BIDMC
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Arabinda Pani, HMS III
Gillian Lieberman, MD
CT: Appendicolith
http://www.madisonradiologists.com/SvcCTAbdominalPain.htm
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Arabinda Pani, HMS III
Gillian Lieberman, MD
Arrowhead Sign
http://lunis.lumc.edu/radiology/Appendicitis/ctfindings.htm
Mural thickening of the cecum at the
base of an obstructed appendix
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Arabinda Pani, HMS III
Gillian Lieberman, MD
Periappendiceal Abscess
Courtesy of Dr. Damon Soeiro; PACS: BIDMC
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Arabinda Pani, HMS III
Gillian Lieberman, MD
Coronal CT: Abscess
PACS: BIDMC
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Arabinda Pani, HMS III
Gillian Lieberman, MD
Our Patient
Otherwise healthy, 33 year old female at 20 weeks
gestation, presented to ED with 6 days of abdominal
pain.
Pain was described as epigastric and crampy in nature.
Denied nausea, vomiting. Reported loss of appetite,
chills, and a low-grade fever.
Temp 99.4 WBC: 10.2
Abdomen: soft, gravid, diffusely tender to palpation;
no rigidity or rebound tenderness
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Arabinda Pani, HMS III
Gillian Lieberman, MD
Diagnostic Complications in Pregnancy
• Pregnancy alters the
position of the appendix
• Atypical clinical
presentation
• Increased risk of
perforation
• Association with
premature labor,
decreased birth weight
•Ultrasound is modality
of choice but diagnosis
can be impeded by body
habitus and anatomic
displacement of the
appendix
•CT exposes the fetus to
radiation
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Arabinda Pani, HMS III
Gillian Lieberman, MD
Patient Evaluation by Ultrasound
• Focal rounded area of
increased echogenicity
with a hypoechoic rim and
increased vascularity
suspicious for an inflamed
appendix
• Localized to the patient’s
area of tenderness
• Noncompressible
PACS: BIDMC
29
Arabinda Pani, HMS III
Gillian Lieberman, MD
Doppler Ultrasound Findings
• Transverse view demonstrated
increased circumferential flow
in the wall of the appendix,
suggestive of hypervascularity
secondary to inflammation
PACS: BIDMC
30
Arabinda Pani, HMS III
Gillian Lieberman, MD
Diagnosis of Appendicitis in Pregnancy
Diagnostic Findings
• Enlarged appendix >
6mm
• Periappendiceal
inflammatory changes
• T2/fat-suppressed
images: high signal
intensity of an inflamed
appendix
Advantages of MR
•Visualize an abnormal
appendix in atypical
locations
•Visualize adjacent
inflammatory processes
•Different sequences +/-
contrast
•No known biologic risks to
fetus
31
Arabinda Pani, HMS III
Gillian Lieberman, MD
HASTE Sequence, Coronal View
• Appendix location:
posterior and superior
to the uterus
• Distended at:
10 mm in the middle;
18 mm at tip
• Associated fat
stranding
Courtesy of Dr. Eric Zeikus, PACS: BIDMC
32
Arabinda Pani, HMS III
Gillian Lieberman, MD
Sagittal View
• Fluid-filled lumen
• Thickened wall
PACS: BIDMC
33
Arabinda Pani, HMS III
Gillian Lieberman, MD
Conclusion of Case
• Patient proceeded to surgery for a laparoscopic
appendectomy, performed without complications.
• On gross appearance, the appendix was inflamed
and gangrenous.
• Post-op ultrasound demonstrated a normal,
unchanged fetus.
• Pathology: specimen consistent with acute
appendicitis with evidence of perforation
• The mother carried fetus to term, delivered
without complications.
34
Arabinda Pani, HMS III
Gillian Lieberman, MD
Acknowledgements
• Michael Geary, MD
• Arati Khanna, MD
• Damon Soeiro, MD
• Atif Zaheer, MD
• Eric Zeikus, MD
• Gillian Lieberman, MD
• Pamela Lepkowski
• Larry Barbaras
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Arabinda Pani, HMS III
Gillian Lieberman, MD
References
• Birnbaum B A, and Wilson S R. Appendicitis at the Millennium. Radiology 2000
215: 337-348.
• Checkoff JL, Wechsler RJ, Nazarian LN. Chronic Inflammatory Appendiceal
Conditions That Mimic Acute Appendicitis on Helical CT. Am. J. Roentgenol. 2002
179: 731-734
• Cobben LP, Groot I, Haans L et al. MRI for Clinically Suspected Appendicitis
During Pregnancy. Am. J. Roentgenol. 2004 183: 671-675
• Eyvazzadeh AD, Pedrosa I, Rofsky N M et al. MRI of Right-Sided Abdominal Pain
in Pregnancy. Am. J. Roentgenol. 2004 183: 907-914
• Lee J, Jeong YK, Hwang JC, et al. Graded Compression Sonography with
Adjuvant Use of a Posterior Manual Compression Technique in the Sonographic
Diagnosis of Acute Appendicitis Am. J. Roentgenol. 2002 178: 863-868.
• Novelline, RA. Helical CT in Emergency Radiology. Radiology 1999 213: 321-
339.
• Rosen MP, Sands DZ, Esterbrook H, et al. Impact of Abdominal CT on the
Management of Patients Presenting to the Emergency Department with Acute
Abdominal Pain. Am. J. Roentgenol. 2000 174: 1391-1396
• Somani R, Gordon C, McArthur R. Appendicitis in pregnancy: a rare
presentation. CMAJ 2003 168: 1020
• Wise SW, Labuski MR, Kasales CJ, et al. Comparative Assessment of CT and
Sonographic Techniques for Appendiceal Imaging Am. J. Roentgenol. 2001 176:
933-941
Radiologic Diagnosis of Appendicitis
Overview
Epidemiology
Pathophysiology
Complications of Appendicitis
Classic Presentation
Role of Radiologic Diagnosis
Anatomy
Normal Appendix
Ultrasound: Normal Appendix
Normal Appendix: MR
Radiologic Findings of Appendicitis
Plain Film: Calcified Appendicolith
Graded Compression Ultrasound
Appendicitis on Ultrasound
Color Doppler Ultrasound
Appendicolith on US
Perforated Appendix on US
CT Diagnosis
Uncomplicated Appendicitis: CT
Coronal CT: Enhancing Wall
CT: Appendicolith
Arrowhead Sign
Periappendiceal Abscess
Coronal CT: Abscess
Our Patient
Diagnostic Complications in Pregnancy
Patient Evaluation by Ultrasound
Doppler Ultrasound Findings
Diagnosis of Appendicitis in Pregnancy
HASTE Sequence, Coronal View
Sagittal View
Conclusion of Case
Acknowledgements
References