Overview and CT Imaging Examples of Common Colon PathologiesAndy Nguyen

Kellie Schenk

Table of Contents• Normal anatomy• Appendicitis• Diverticulosis• Diverticulitis• Ulcerative colitis• Crohn’s disease• Pseudomembranous c

olitis (C. diff)• Adenocarcinoma

• Quiz cases• References

*You can navigate through the presentation linearly or click on any of the above links to jump to that specific section

Normal Anatomy

Return to Table of ContentsCT Abdomen, Axial view

Appendicitis

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Note enlargement of the appendix (arrows), intraluminal fluid, and adjacent inflammatory stranding

• Demographics:• Any age, most commonly

10-30 years old• Slightly more common in

males (1.4 : 1)

• Clinically:• Abdominal pain, often

RLQ• Nausea• Vomiting• Fever

Appendicitis (cont’d)

• Compare to normal appendix

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Normal air-filled appendix (arrow)

Diverticulosis

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Moderate diverticulosis in the sigmoid colon (arrows)

• Demographics:• Rare before age 40• Incidence increases with

age• May be associated with

low-fiber diet

• Clinically:• Most often

asymptomatic, diagnosed incidentally

• May be associated with lower abdominal discomfort, bloating, constipation

Diverticulitis

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Note wall thickening in the sigmoid colon (arrows) and adjacent inflammatory changes in the pericolic fat

• Demographics:• See Diverticulosis

• Clinically:• Abdominal pain, often

LLQ• Nausea• Vomiting• Constipation or diarrhea• Fever

Ulcerative Colitis

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• Demographics:• Peak incidence between

15 – 30 years old• Equal incidence in males

and females

• Clinically:• Diarrhea (can be > 10

loose stools / day), often bloody

• Rectal bleeding• Passage of mucus with

defecation• Abdominal pain• Constipation• Fever

Note diffuse thickening of the sigmoid colon (arrows) and minimal adjacent inflammatory stranding

Crohn’s Disease

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• Demographics:• Two peaks of incidence:

15 – 30 and 50 – 80 years old

• Equal incidence in males and females

• Clinically:• Abdominal pain• Diarrhea (usually non-

bloody)• Steatorrhea• Fatigue• Oral ulcers

Note thickening of the terminal ileum (curved arrow) and cecum (straight arrow) and inflammatory changes in the adjacent fat

Pseudomembranous colitis

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Note diffuse wall thickening throughout the colon (arrows), and pericolic inflammation

• Demographics:• Most commonly caused

by C.diff overgrowth following treatment with antibiotics

• Advanced age is risk factor

• Clinically:• Watery diarrhea (5-10x

per day)• Abdominal cramps• Hematochezia• Fever

Adenocarcinoma (Colon)• Demographics:

• Uncommon before age 40; 90% of cases are after age 50

• In the US, male incidence is 25% higher than female

• Clinically:• Abdominal pain• Change in bowel habits• Hematochezia or melena• Iron deficiency anemia

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Note circumferential thickening of the cecum (curved arrows) and a hypodense focus within the wall which is due to necrosis (straight arrow)

Quiz Cases

• Image presented first• Clinical history provided second• Diagnosis given last

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Case #1

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• 71 year old Male• LLQ abdominal

pain• Constipation• Nausea• Vomiting• Fever

Diagnosis: Diverticulitis Note diverticuli (arrows) and fascial thickening (arrowheads), indicating diverticulitis

Case #2

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• 17 year old Female• Frequent, bloody

diarrhea with mucus• Abdominal pain• Rectal bleeding• Fever

Diagnosis: Ulcerative colitisNote mucosal erosions (arrows) and normal luminal caliber and ascites (A)

Case #3

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• 55 year old Male• Abdominal pain• Thin, pencil-like

stools• Melena• Weight loss

Diagnosis: Adenocarcinoma of the colonNote erosion into the anterior abdominal wall (arrow)

Case #4• 61 year old

Female• Abdominal pain• Fever• 8 episodes of

diarrhea / day• Recently treated

for bacterial sinusitus

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Diagnosis: Pseudomembranous colitisNote diffuse colonic wall thickening, pericolic inflammation, and ascites. The thickened walls and small amount of contrast between folds has the appearance of an accordion (accordion sign)

Case #5

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• 73 year old Female

• No symptoms• Findings

incidentally noted on abdominal CT

Diagnosis: DiverticulosisNote diverticuli (arrows)

Case #6• 23 year old

Male • RLQ abdominal

pain• Nausea• Vomiting• Fever• Loss of appetite

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Diagnosis: Appendicitis

Note the dilated, fluid-filled appendix (arrows) and inflammatory changes in the adjacent fat

Case #7

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• 53 year old Female• Abdominal pain• Steatorrhea• Diarrhea• Fatigue

Diagnosis: Crohn’s DiseaseNote thickening of the terminal ileum and cecum (white arrows) along with fibrofatty proliferation (arrowheads). An enlarged lymph node is also visible (black arrow)

References• Horton KM, Corl FM, Fishman EK. CT Evaluation of the Colon: Inflammatory Disease. Radiographics,

March 2000 20:2 399-418• Horton KM, Abrams RA, Fishman EK. Spiral CT of Colon Cancer: Imaging Features and Role in

Management. Radiographics, 2000; 20:419–430• Gore RM, Balthazar EJ, Ghahremani GG, Miller FH. CT Features of Ulcerative Colitis and Crohn’s

Disease. AJR, 1996; 167;3-15• Thoeni RF, Cello JP. CT Imaging of Colitis. Radiology, 2006; 240;623-638• http://www.meddean.luc.edu/lumen/MedEd/Radio/curriculum/Surgery/bowel_obstruction.htm• http://www.meddean.luc.edu/lumen/meded/Radio/curriculum/Surgery/Diveriticulitis1.htm• Demographic information and clinical signs/symptoms: www.uptodate.com