Imaging of IBD and Other Colitides Cynthia Walsh, MD FRCPC Department of Radiology

Outline Three quiz questions Imaging modalities available Ulcerative Colitis Crohn’s Disease Three quiz questions- answers

Question 1 The typical distribution of ulcerative colitis is described as: Affects any segment of the gastrointestinal tract, but preferentially localizes in the terminal ileum. Begins in the rectum and extends proximally with segmental discontinuous involvement. Begins in the rectum and extends proximally with contiguous spread. Transmural disease of the bowel wall, causing fistulas and abscesses.

Question 2 What critical finding is in this upright Chest X-ray?

Question 3 What extra colonic finding is demonstrated in this patient with Crohn’s Disease?

What imaging modalities are used to image the bowel? Plain Films Enema Barium - Single or double contrast Water-soluble CT Techniques CT (with or without IV or oral contrast) CT Enterography (small bowel imaging) Virtual Colonography (colon imaging) MRI (*** NO IONIZINH RADIATION) MR Enterography (small bowel) Perianal disease (for fistulas or abscesses)

Plain Film of the Abdomen Projections: supine and upright (or lateral decubitus if cannot stand) To Exclude: intestinal obstruction toxic megacolon pneumoperitoneum

Barium or Water Soluble Enema DCBE Dynamic evaluation of the colon performed under fluoroscopy after rectal infusion of contrast Colon wall is coated with: Barium only (single contrast Barium Enema) Barium and air (double contrast Barium Enema) Water soluble contrast (Water Soluble Enema) Can demonstrate polyps, colon cancer, diverticula, strictures, fistulas, ulcers, leak, stenosis (etc.) Lesion detection depends largely on the operator and lesion size SCBE

Single contrast barium enema (SCBE) Indications for Different Types of Enema: Single vs. Double contrast Barium vs. Water Soluble Water Soluble Enema: Suspected perforation pre or post-operative study (don’t want barium in the peritoneal cavity) Single contrast barium enema (SCBE) Differentiate mechanical obstruction from pseudo-obstruction (Ogilvie syndrome Exclude anastomotic leak (use water soluble) or stenosis Limited information (can miss mucosal abnormalities, polyps and cancer) Double contrast barium enema (DCBE): Now nearly OBSOLETE For polyps and Colon Cancer: Replaced by CT Colonography For IBD: Small bowel: CT Enterography or MR Enterography Colon: Primarily Colonoscopy

Double Contrast Barium Enema Single Contrast Barium Enema Double Contrast Barium Enema Polyp not visible polyp

Double Contrast Barium Enema: Two Polyps

CT Can us IV contrast, Oral contrast, neither or both (depends on the indication). Main indications for CT of the Colon: Stage Colon Cancer Abdominal pain Complications from colitis Determine the site or cause of bowel obstruction Diagnose ischemia

CT or MR Enterography Ingest 1.5 L of oral contrast (PEG) Distends the small bowel Main indications: Diagnosis of small bowel IBD (where colonoscopy cannot get) Complications of IBD (stenosis, obstruction, fistula, abcess etc.) Preoperative evaluation Evaluation of anemia or GI bleeding in the context of negative colonoscopy and endoscopy

CT Colonography Main indications: Find polyps and colon cancer if colonoscopy is incomplete or contraindicated Contraindicated in the setting of acute colitis.

Imaging of IBD: What is the best imaging test? It depends on the Clinical Question: Establish diagnosis of IBD, or determine the extent of disease Colon: Colonoscopy Small Bowel: CT enterography, or MR enterography (MR especially useful in young patients, to avoid radiation) Complications of inflammatory disease Plain film CT Perianal disease: MRI

Ulcerative Colitis Proximal extension from rectum CONTIGUOUS disease (no skip lesions) Mucosal disease Increased risk of colon cancer On Double Contrast Barium Enema Mucosal granularity Collar button ulcers Single contrast enema not much use

Ulcerative Colitis on DCBE Contiguous mucosal irregularity in the rectum and sigmoid Normal mucosa

Ulcerative Colitis on DCBE: Collar button ulcers

Ulcerative Colitis: Featureless colon (“lead pipe”) Normal DCBE

Ulcerative Colitis on CT Colonic wall thickening with contiguous spread (without skipped segments)

Imaging of Crohn’s Disease: Frequently involves the terminal ileum, however can involve any portion of GI tract Discontinuous (skip lesions) Transmural Apthoid ulcers Branching/linear ulcers (cobblestoning) Fistulas, sinus tracts, abscesses Perianal disease

Crohn’s Disease on DCBE: apthoid ulcers

Crohn’s Disease on DCBE: strictures and fistulas Mucosal irregularity fistula

Crohn’s Disease: Terminal ileum involvement on MR Enterography - Layered appearance of the bowel wall (“target sign”) - Submucosal edema - Mural hypervascularity: evidence of inflammatory activity

Crohn’s Disease: Terminal ileum involvement on CT

Crohn’s Disease on CT Entero-enteric fistula Pre-stenotic dilatation Mesenteric hyperemia: engorgement of mesenteric vessels

Crohn’s Disease – Extra colonic Disease: Sacroiliitis Erosions and sclerosis in the SI joints Normal

Perianal fistula on MRI Crohn’s Disease: Perianal fistula on MRI

Enema and CTC are contraindicated (as in any acute colitis) Toxic Megacolon Acute complication of colitis Risk of perforation Most common in UC, but can occur with any colitis. Imaging recommended CT or Plain film Enema and CTC are contraindicated (as in any acute colitis)

Toxic Megacolon: Imaging Findings Colon Dilatation Best seen in the transverse colon, but can affect the whole colon Thumb printing (mural edema) Colonic Dilatation on imaging can raise the possibility of Toxic Megacolon. However, this is ultimately a clinical diagnosis.

Toxic Megacolon - Upright Chest x-ray (in the same patient) - Dilated colon with thumb printing

Toxic Megacolon: Perforation Free air under the diaphragm (Pneumoperitoneum)

Ischemic Colitis

Ischemic Colitis Air in the wall of the ascending colon = PNEUMATOSIS

Thumbprinting in transverse colon DDx: colitis (ischemic, inflammatory, infectious)

Question 1 The typical distribution of ulcerative colitis is described as: Affects any segment of the gastrointestinal tract, but preferentially localizes in the terminal ileum. Begins in the rectum and extends proximally with segmental discontinuous involvement. Begins in the rectum and extends proximally with contiguous spread. Transmural disease of the bowel wall, causing fistulas and abscesses.

Question 2 What critical finding is in this upright Chest X-ray? Pneumoperitoneum -free air under the diaphragm -bowel perforation

Question 3 What extra colonic finding is demonstrated in this patient with Crohn’s Disease? SACROILIITIS Normal

Questions or comments? cwalsh@ottawahospital.on.ca Thank you Questions or comments? cwalsh@ottawahospital.on.ca