Man with abdominal pain.

Our appreciation is extended to Dr. Remy Lobo, Indiana University Department of Radiology, for contributing this case.

Man with abdominal pain.

Man with abdominal pain.

Findings:

Axial Image 1:  Long segment stenosis of the distal pelvic ileum, inflammation of the terminal ileum at the ileocecal valve.  Prominent vasculature, mucosal enhancement

Axial Image 2:  Comb sign, dense vessels in the RLQ, feeding active inflammation in distal ileum

Axial Image 3:  Small bowel target (double halo) sign in RLQ.  Also a fibrostenotic lesion right of midline seen just anterior/medial to external iliac artery, showing enhanced wall, narrowing, with near occlusion of lumen, .

Axial Image 4:  Dilated small bowel with stenotic transition point right lower quadrant with mild mesenteric inflammation.

• Crohn's disease
• Ulcerative colitis
• Infection (Yersinia, AIDS patients get mycobacterium / CMV)
• Ischemic changes and mesenteric adenitis (unlikely, wrong age groups)
• Radiation enteritis, metastatic disease

Man with abdominal pain.

Key points - Crohn's disease: 

• Chronic, recurrent, segmental, granulomatous inflammatory bowel disease
• Can occur anywhere along GI tract. Terminal ileum in 95%, colon in one-fourth, rectum in up to half.
• Skip lesions, noncaseating granulomas, cobblestone mucosa
• Pertinent ancillary findings include sinus tract or fistulae, abscess, adhesions, strictures, and "active" inflammation or not.
• Discontinuous asymmetric wall thickening > 1 cm
• Small bowel wall thickening and hyperemia with mesenteric fat proliferation are very suggestive of Crohn's.
• Minimal narrowing in acute or noncicatrizing phase
  • Soft tissue inner ring (mucosa)
  • Low-density middle ring (submucosal edema/fat)
  • ST density outer ring (muscularis propria serosa)
  • Proliferation of mesenteric fat ± lymphadenopathy
  • "Target" or "double halo" sign
    • Intense enhancement of mucosa, muscularis propria
    • ? attenuation in edematous thickened submucosa
• Increased luminal narrowing; no "target" sign in chronic or cicatrizing phase
  • Mural stratification lost: Indistinct mucosa, submucosa, muscularis propria
  • Homogeneous attenuation of thickened bowel wall
  • Abscesses, fistulas, sinus tracts
  • Mesenteric changes: Abscess, fibro-fatty areas, nodes
  • Perianal disease, enlarged mesenteric lymph nodes
  • "Comb" sign: Mesenteric hyper-vascularity (dilatation, tortuosity, wide spacing)
  • ST density inner ring (mucosa)
• Immunology vs. nutritional vs.genetic basis for disease
• Varied presentation, treatment includes diet and immune modulators

References: 

1. CT enteroclysis in small bowel Crohn's disease, MD Kohli, DD Maglinte.  Eur J Radiol. 2009 Mar;69(3):398-403..
2. CT Enteroclysis. DDT Maglinte, K Sandrasegaran, JC Lappas, M Chiorean. December 2007 Radiology, 245, 661-671.

Man with abdominal pain.