Crohn’s Disease

  • Etiology: idiopathic inflammatory bowel disease
  • Imaging: transmural bowel inflammation affecting anywhere in gastrointestinal tract but terminal ileum is classic location, skip lesions
  • CT + MRI signs of active disease: mucosal hyperenhancement, wall thickening, prominent vasa recta (comb sign), mesenteric infiltration of fat, hyperintense on T2, hypoperistalsis, restricted diffusion
  • Complications: stricturing of small bowel, penetrating fistula + abscess formation, sacroiliitis, primary sclerosing cholangitis, avascular necrosis, pancreatitis, nephrolithiasis, cholelithiasis

Cases of Crohn’s Disease

Small bowel follow through of Crohn's disease
AXR AP from a small bowel follow through shows bowel fold thickening in the proximal ileum in the left lower quadrant and bowel lumenal narrowing in the mid ileum in the midline that continues to the terminal ileum in the right lower quadrant.
CT of Crohn's disease with fistula and abscess
Axial CT with contrast of the abdomen shows a thick-walled mass that is filled with air and oral contrast that is located medial to the oral contrast-filled thickened ascending colon and above the right psoas muscle. An extensive amount of inflammatory change is seen in the mesenteric fat in the right lower quadrant.
Gross pathological image of Chron's disease
Gross pathological image of the terminal ileum shows markedly thickened intestinal wall and adherent pericolonic fat (“fat-wrapping”).