Crohn Disease Part 2: Penetrating Disease and Mesenteric Inflammation

Audience: Radiologists and Radiology Residents and Fellows

Learning Objectives: At the end of this exhibit the radiologist should be able to differentiate the imaging findings of penetrating disease and mesenteric inflammation associated with Crohn disease.

Fistulas can be classified as simple, complex or perianal. Description of a fistula should include the involved segments of bowel and any other involved organs such as the bladder, fallopian tubes, or skin.

Inflammatory Mass - Ill-defined mass-like process with mixed fat and soft tissue attenuation or signal intensity. Commonly referred to as phlegmon, which is now discouraged.

Abscess - Fluid collection with rim hyperenhancement with or without gas. Often treated with percutaneous drainage.

Imaging findings of mesenteric inflammation:
Perienteric edema
Engorged vasa recta
Mesenteric fibrofatty proliferation
Mesenteric venous thrombosis/occlusion
Adenopathy

Summary- Penetrating disease and mesenteric inflammation manifest as:
Fistula: simple, complex, perianal
Perienteric edema
Engorged vasa recta
Mesenteric venous thrombosis/occlusion
Adenopathy
Fibrofatty mesenteric change
Inflammatory mass/abscess