Crohn disease of small bowel: multidetector row CT with CT enteroclysis, dynamic contrast enhancement, CT angiography, and 3D imaging.

BACKGROUND: CT could be used to evaluate abnormalities in the bowel wall, mesentery, adjacent structures, vasculature, and even the activity of Crohn disease (CD). To our knowledge, few direct comparisons of CD characterization using multidetector row CT with dynamic contrast enhancement, 3D imaging, CT angiography (CTA), and CT-enteroclysis (CT-E) on the same cohort of patients. The purpose of this study was to evaluate the diagnostic value of CD using multidetector helical CT with CT-E, dynamic contrast enhancement, 3D imaging, and CTA.

METHODS: Twenty-eight patients known or suspected CD underwent CT-E, dynamic contract enhancement, CTA, and 3D imaging. The multidetector CT series images were performed on eight-slice CT scanner. All the examinations were performed when water was used as an oral contrast starting 25 s after 140 mL of intravenous contrast agent was administered, followed by portal venous phase (60 s), and a 60-70 s delay, then sending 1.25-mm slices to the 3D workstation, CT angiograms and 3D images were reconstructed. All the images were reviewed to detect abnormalities of CD. The abnormalities of the bowel wall, mucosal and submucosal ulceration, prominent perienteric vasculature, sinus tracts or fistulae, abscess were evaluated.

RESULTS: Crohn disease was diagnosed in 28 patients by CT images, and 54 inflammatory segments were revealed. In active inflammatory cases, the diseased bowel wall thickened and the enhancement of diseased bowel wall increased significantly in 34 inflammatory segments of 22 cases, the enhancement of diseased bowel wall increased significantly but without the wall thickened in three patients. Prominent vasculature was found in CTA and 3D images in 21 patients with active diseases. In 16 patients, the sharp interface between bowel and mesentery was lost and the attenuation of fat increased. Sinus tracts or fistulae were observed in eight patients, four of 28 patients demonstrated abscesses, all were active inflammatory patients. In three chronic inflammatory patients, normal bowel, bowel lumen stricture, and the normal enhancement of the wall were displayed.

CONCLUSION: The abnormalities of CD and its complications can be identified by multidetector CT with CT-E, dynamic enhancement, CTA, and 3D imaging, and they are important methods in diagnosing CD. Complications of CD can be shown better when CT-E is performed.