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 1The typical distribution of ulcerative colitis is described as:

1. Affects any segment of the gastrointestinal tract, but preferentially localizes in the terminal ileum.

2. Begins in the rectum and extends proximally with segmental discontinuous involvement.

3. Begins in the rectum and extends proximally with contiguous spread.

4. Transmural disease of the bowel wall, causing fistulas and abscesses.

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

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

Question 3

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

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

DCBE

SCBE

Indications for Different Types of Enema: Single vs. Double contrastBarium 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

Polyp not visible polyp

Double Contrast Barium Enema: Two Polyps

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:

1. Establish diagnosis of IBD, or determine the extent of disease

a. Colon: Colonoscopy b. Small Bowel: CT enterography, or MR enterography

(MR especially useful in young patients, to avoid radiation)

2. Complications of inflammatory diseasea. Plain filmb. CT

3. Perianal disease: MRI

Ulcerative Colitis

Proximal extension from rectumCONTIGUOUS disease (no skip lesions)Mucosal diseaseIncreased 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 irregularityin 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

• Stricture• 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

Mesenteric hyperemia: engorgement of mesenteric vessels

Entero-enteric fistula

Pre-stenotic dilatation

Crohn’s Disease on CT

Erosions and sclerosis in the SI joints

Normal

Crohn’s Disease – Extra colonic Disease: Sacroiliitis

Crohn’s Disease: Perianal fistula on MRI

Toxic Megacolon Acute complication of colitis Risk of perforation Most common in UC, but can occur with any

colitis.

Imaging recommended

• CT or Plain filmEnema 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

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

Free air under the diaphragm (Pneumoperitoneum)

Toxic Megacolon: Perforation

Ischemic Colitis

Air in the wall of the ascending colon = PNEUMATOSIS

Ischemic Colitis

• Thumbprinting in transverse colon

• DDx: colitis (ischemic, inflammatory, infectious)

Question 1The typical distribution of ulcerative colitis is described as:

1. Affects any segment of the gastrointestinal tract, but preferentially localizes in the terminal ileum.

2. Begins in the rectum and extends proximally with segmental discontinuous involvement.

3. Begins in the rectum and extends proximally with contiguous spread.

4. Transmural disease of the bowel wall, causing fistulas and abscesses.

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

Pneumoperitoneum

-free air under the diaphragm

-bowel perforation

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

Question 3

SACROILIITISNormal

THANK YOU

Questions or comments?

cwalsh@ottawahospital.on.ca