Endoscopy & biopsy-proven case of "Crohn's disease"

Crohn's disease, like ulcerative colitis, is an idiopathic inflammatory bowel disease (IBD), characterized by widespread gastrointestinal tract involvement, typically with skip lesions - thereby its synonym regional enteritis - and frequently systemic involvement.

CT examination can be carried out with both intravenous and intraluminal contrast (positive or negative).

• fat halo sign
• comb sign
• bowel wall enhancement
• bowel wall thickening (1-2 cm) which is most frequently seen in the terminal ileum (present in up to 83% of patients)
• strictures and fistulae
• mesenteric / intra-abdominal abscess or phlegmon formation 
• abscesses are eventually seen in 15-20% of patients.

 The comb sign refers to the hypervascular appearance of the mesentery in active Crohn's disease.  Fibrofatty proliferation and perivascular inflammatory infiltration outline the distended intestinal arcades. This forms linear densities on the mesenteric side of the affected segments of the small bowel, which gives the appearance of the teeth of a comb.