Inflammatory bowel disease imaging: Current practice and future directions

Abstract

The purpose of this paper is to evaluate the role of imaging in inflammatory bowel disease (IBD), including detection of extraluminal complications and extraintestinal manifestations of IBD, assessment of disease activity and treatment response, and discrimination of inflammatory from fibrotic strictures. IBD is a chronic idiopathic disease affecting the gastrointestinal tract that is comprised of two separate, but related intestinal disorders; Crohn's disease and ulcerative colitis. The paper discusses, in detail the pros and cons of the different IBD imaging modalities that need to be considered in order to optimize the imaging and clinical evaluation of patients with IBD. Historically, IBD evaluation of the bowel has included imaging to assess the portions of the small bowel that are inaccessible to optical endoscopic visualization. This traditionally was performed using barium fluoroscopic techniques; however, cross-sectional imaging techniques (computed tomography and magnetic resonance imaging) are being increasingly utilized for IBD evaluation because they can simultaneously assess mural and extramural IBD manifestations. Recent advances in imaging technology, that continue to improve the ability of imaging to noninvasively follow disease activity and treatment response, are also discussed. This review article summarizes the current imaging approach in inflammatory bowel disease as well as the role of emerging imaging modalities.

Keywords: Computed tomography; Crohn’s disease; Imaging; Inflammatory bowel disease; Magnetic resonance imaging; Ulcerative colitis.

Figure 1

Extraintestinal and extraluminal manifestations of inflammatory bowel disease depicted on imaging. A: Primary sclerosing cholangitis depicted on magnetic resonance cholangio-pancreatography evidenced as intermittent beading and structuring of the intrahepatic bile ducts; B: Penetrating Crohn’s disease depicted on computed tomography as enhancing fistulous tracks (arrows) of an enterocolonic fistula, with associated abscess formation (asterisk) in the adjacent iliacus musculature.

Figure 2

Computed tomography enteroclysis depiction of small bowel stricture. Fluoroscopic (A) and computed tomography (B) images from an enteroclysis demonstrating a 9 cm stricture in the mid small bowel (arrows) with proximal small bowel dilation (asterisks), which was confirmed during subsequent surgical resection.

Figure 3

Active Crohn’s terminal ileitis depicted on computed tomography enterography and magnetic resonance enterography in the same patient. Serial computed tomography enterography (A) and magnetic resonance enterography (B) studies demonstrate marked wall thickening and hyperenhancement (arrows) just proximal to the ileocecal valve consistent with active disease, as confirmed by endoscopy.

Figure 4

Abnormal bowel peristalsis visualized by cinematic magnetic resonance enterography imaging. Two static images from a cinematic steady state free precession image series demonstrate multiple normally peristalsing small bowel loops (A, B: arrowheads) as well as a fixed hypoperistaltic loop of inflamed small bowel (B; arrows). This loop also demonstrates wall thickening and mesenteric hypervascularity consistent with active inflammation.

Figure 5

Perianal fistulizing Crohn’s disease depicted on magnetic resonance fistulography. Axial short tau inversion recovery (A) and coronal (B) T2-weighted (B) images demonstrate a complex perianal fistula at the 6 o’clock position (A; arrow) with an intersphincteric component (A; asterisks) as well as a transphincteric track extending to the skin to the right of midline (B; arrow).

Figure 6

Dual energy computed tomography enterography in inflammatory bowel disease. Standard (A) and Iodine monochromatic (B) images from a dual energy computed tomography enterography demonstrate a polypoid lesion in the distal ileum (arrow) that was only appreciated on the Iodine images and found to represent an inflammatory pseudopolyp at endoscopy.