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

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

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

Appendicitis Demographics: Clinically: 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

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

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) Return to Table of Contents

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 Return to Table of Contents

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 Return to Table of Contents

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 Return to Table of Contents

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

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

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

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

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

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

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

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

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

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

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