imaging of ibd and other colitides cynthia walsh, md frcpc department of radiology
TRANSCRIPT
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