Clin Endosc.  2013 Jul;46(4):327-366.

Computed Tomography Enterography for Evaluation of Inflammatory Bowel Disease

• Park MJ
• Lim JS

Abstract

Computed tomography enterography (CTE) has become a main modality for the evaluation of inflammatory bowel disease (IBD). It simultaneously offers visualization of the small bowel and extraintestinal status, which is helpful for diagnosing IBD. Crohn disease has long segmental enhancing wall thickening related with the eccentric longitudinal distribution. In addition, mural stratification, fibrofatty proliferation, positive comb sign by increased mesenteric vascularity and internal/perianal fistula are characteristics of Crohn disease and can be identified on CTE. Short segmental inflammatory wall thickening and the central low attenuated lymph nodes are favorable CT finding of intestinal tuberculosis. A geographic, relatively large, and deep penetrating ulcer with bowel wall thickening and mural hyperenhancement in ileocecal area are characteristics of intestinal Behcet disease. Each of CTE findings for the IBDs is helpful for differential diagnosis. The main disadvantage of this technique is the requisite radiation exposure of patients, particularly in young patients. However, recent development of advanced CT techniques is promising for radiation dose reduction without compromising diagnostic image quality.

Keyword

Computed tomography enterography; Inflammatory bowel diseases; Crohn disease; Intestinal tuberculosis; Behcet syndrome

MeSH Terms

Behcet Syndrome
Crohn Disease
Diagnosis, Differential
Fistula
Humans
Inflammatory Bowel Diseases
Lymph Nodes
Tuberculosis
Ulcer

Figure

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  Fig. 1 Active inflammatory Crohn disease in a 28-year-old man. (A) Axial computed tomography enterography images demonstrate multifocal segmental mural hyperenhancement and trilaminar mural stratification in the ileum (arrows), suggesting active disease. (B) Also note engorged vasa recta (arrowheads) and increased attenuation of the mesenteric fat (asterisk).

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  Fig. 2 Active inflammatory Crohn disease with extraenteric complications in a 29-year-old man. (A) Coronal computed tomography enterography images demonstrate multifocal segmental stricture showing wall thickening, mural hyperenhancement and stratification (arrows), and engorged vasa recta, "comb sign" (circle). (B, C) Also noted a mesenteric abscess (arrowheads in B) adjacent to the enteroenteric fistula (arrow in C).

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  Fig. 3 Crohn disease in a 31-year-old man. (A, B) Coronal computed tomography enterography images show pseudosacculation along the antimesenteric border of small bowel (arrowheads). (B) Fibrofatty proliferation is also demonstrated in the mesentery (circle). (C) Sinus tract arising in the terminal ileum (arrow) which shows mural hyperenhancement and stratification, suggesting active inflammatory disease, is also noted.

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  Fig. 4 Fibrostenosing Crohn disease in a 32-year-old man. Axial computed tomography enterography image shows a segmental stricture involving proximal ileal loop. Homogenous mural thickening is seen at the strictured segment without mural hyperenhancement, suggesting fibrostenotic disease (arrow).

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  Fig. 5 Crohn disease in a 34-year-old woman. (A) Axial computed tomography enterography image shows enteroenteric fistula involving ileal loops (arrow). (B) Perianal fistula is also seen (arrow).

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  Fig. 6 Intestinal tuberculosis in a 37-year-old woman. Coronal computed tomography enterography image shows circumferential wall thickening in the ileocecal valve area (arrow). Such ileocecal involvement is the most common form of intestinal tuberculosis.

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  Fig. 7 Intestinal tuberculosis in a 52-year-old woman. Coronal computed tomography enterography image shows two short segmental circumferential enhancing wall thickenings involving proximal ileal loop (arrows). Associated prestenotic bowel dilatation is also seen.

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  Fig. 8 Intestinal tuberculosis in a 27-year-old woman. Axial computed tomography enterography image shows enhanced wall thickening involving cecum and terminal ileum with patulous ileocecal valve (arrows). Associated central low attenuated lymph nodes are seen at the ileocecal mesentery, suggesting caseous necrosis (arrowheads).

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  Fig. 9 Crohn disease mimicking intestinal tuberculosis in a 53-year-old man. Relatively short segmental circumferential stricture is suspected in the distal ileal loop (arrow). Associated angulation is also seen. There is no remarkable finding in the mesentery. Preoperative computed tomography diagnosis was intestinal tuberculosis, but Crohn disease was confirmed after segmental resection of the small bowel loop.

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  Fig. 10 Behcet disease in a 53-year-old woman. Axial computed tomography enterography image shows focal wall thickening with a deep penetrating ulcer (arrowheads) in the terminal ileum, and mesenteric fat infiltration around the ileocecal area.

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  Fig. 11 Behcet disease in a 41-year-old man. (A, B) Axial computed tomography enterography images show wall thickening and several large, deep ulcers (arrowheads in A) in the terminal ileum with aneurysmal dilatation (asterisk in B).

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  Fig. 12 Recurrent Behcet disease in a 30-year-old woman. Coronal computed tomography enterography image shows an ulceration with peripheral enhancement at the anastomosis site of ileocecectomy (arrows).

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  Fig. 13 Radiation dose reduction by application of advanced techniques and computed tomography (CT) protocol optimization. Total dose-length product (DLP) was 861 mGycm in CT enterography (CTE) obtained in 2011 (upper row). Follow-up CTE was taken in the same patient with Crohn disease in 2013. Total DLP was remarkably decreased as 186 mGycm (lower row). In the recent CTE exam, tube current modulation, lowering tube potential, and iterative reconstruction techniques were applied. Only singe portal phase imaging was performed, whereas dual dynamic phases had been obtained in 2011. The similar image quality can be identified, comparing picture-in-picture images.

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