1. Overview and CT Imaging Examples of Common Colon Pathologies
Andy Nguyen
Kellie Schenk

2. Table of Contents Normal anatomy Appendicitis Diverticulosis
Diverticulitis
Ulcerative colitis
Crohn’s disease
Pseudomembranous colitis (C. diff)
Adenocarcinoma
Quiz cases
References
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3. Normal Anatomy
CT Abdomen, Axial view
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4. Appendicitis Demographics: Clinically:
Any age, most commonly years old
Slightly more common in males (1.4 : 1)
Clinically:
Abdominal pain, often RLQ
Nausea
Vomiting
Fever
Note enlargement of the appendix (arrows), intraluminal fluid, and adjacent inflammatory stranding
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5. Appendicitis (cont’d)
Compare to normal appendix
Normal air-filled appendix (arrow)
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6. Diverticulosis Demographics: Clinically: 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
Moderate diverticulosis in the sigmoid colon (arrows)
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7. Diverticulitis Demographics: Clinically: See Diverticulosis
Abdominal pain, often LLQ
Nausea
Vomiting
Constipation or diarrhea
Fever
Note wall thickening in the sigmoid colon (arrows) and adjacent inflammatory changes in the pericolic fat
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8. Ulcerative Colitis Demographics: Clinically:
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
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9. Crohn’s Disease Demographics: Clinically:
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
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10. Pseudomembranous colitis
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
Note diffuse wall thickening throughout the colon (arrows), and pericolic inflammation
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11. 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
Note circumferential thickening of the cecum (curved arrows) and a hypodense focus within the wall which is due to necrosis (straight arrow)
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12. Quiz Cases Image presented first Clinical history provided second
Diagnosis given last
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13. Case #1 71 year old Male LLQ abdominal pain Constipation Nausea
Vomiting
Fever
Diagnosis: Diverticulitis
Note diverticuli (arrows) and fascial thickening (arrowheads), indicating diverticulitis
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14. Case #2 17 year old Female Frequent, bloody diarrhea with mucus
Abdominal pain
Rectal bleeding
Fever
Diagnosis: Ulcerative colitis
Note mucosal erosions (arrows) and normal luminal caliber and ascites (A)
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15. Case #3 55 year old Male Abdominal pain Thin, pencil-like stools
Melena
Weight loss
Diagnosis: Adenocarcinoma of the colon
Note erosion into the anterior abdominal wall (arrow)
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16. Case #4 61 year old Female Abdominal pain Fever
8 episodes of diarrhea / day
Recently treated for bacterial sinusitus
Diagnosis: Pseudomembranous colitis
Note 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)
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17. Case #5 73 year old Female No symptoms
Findings incidentally noted on abdominal CT
Diagnosis: Diverticulosis
Note diverticuli (arrows)
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18. Case #6 23 year old Male RLQ abdominal pain Nausea Vomiting Fever
Loss of appetite
Diagnosis: Appendicitis
Note the dilated, fluid-filled appendix (arrows) and inflammatory changes in the adjacent fat
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19. Case #7 53 year old Female Abdominal pain Steatorrhea Diarrhea Fatigue
Diagnosis: Crohn’s Disease
Note thickening of the terminal ileum and cecum (white arrows) along with fibrofatty proliferation (arrowheads). An enlarged lymph node is also visible (black arrow)
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20. References
Horton KM, Corl FM, Fishman EK. CT Evaluation of the Colon: Inflammatory Disease. Radiographics, March :
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;
Demographic information and clinical signs/symptoms: