Overview and CT Imaging Examples of Common Colon Pathologies

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

3. Normal Anatomy CT Abdomen, Axial view Return to Table of Contents

4. Appendicitis • 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 Note enlargement of the appendix (arrows), intraluminal fluid, and adjacent inflammatory stranding Return to Table of Contents

5. Appendicitis (cont’d) • Compare to normal appendix Normal air-filled appendix (arrow) Return to Table of Contents

6. Diverticulosis • 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 Moderate diverticulosis in the sigmoid colon (arrows) Return to Table of Contents

7. Diverticulitis • Demographics: • See Diverticulosis • Clinically: • 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 Return to Table of Contents

8. Ulcerative Colitis • 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 Return to Table of Contents

9. Crohn’s Disease • 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 Return to Table of Contents

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 Return to Table of Contents

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) Return to Table of Contents

12. Quiz Cases • Image presented first • Clinical history provided second • Diagnosis given last Return to Table of Contents

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 Return to Table of Contents

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) Return to Table of Contents

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) Return to Table of Contents

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) Return to Table of Contents

17. Case #5 • 73 year old Female • No symptoms • Findings incidentally noted on abdominal CT Diagnosis: Diverticulosis Note diverticuli (arrows) Return to Table of Contents

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 Return to Table of Contents

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) Return to Table of Contents

20. 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