Radiology: MR imaging validates Crohn's scoring standard
A study in the September issue of Radiology reports that MR imaging features of acute inflammation have been validated against a histopathological reference standard in Crohn's disease.

According to Shonit Punwani, PhD, department of specialist x-ray, University College London Hospitals in the U.K., and colleagues, the evaluation of Crohn's disease is critical to optimize therapeutic strategy. In the case of Crohn's, the evaluation is based on certain clinically derived scores, biochemical markers, endoscopic and radiologic findings.

The Crohn’s Disease Activity index and the Harvey-Bradshaw index are the standard of reference, but these scoring systems have some limitations as sometimes patients with quiescent disease receive high scores, while disease activity is underestimated in other patients. So the authors’ goal in this study was to validate MR imaging features of Crohn's disease activity against a matched histopathologic reference standard.

Preoperative MR imaging was performed on 18 patients with Crohn's disease who were undergoing elective small bowel resection  All patients underwent MR enterography within two weeks prior to surgery. The MR enterography was performed using a standard small bowel protocol and the diseased small bowel was excised per usual surgical practice.

The histologic matching was achieved by imaging the ex vivo surgical specimens. Grading of acute inflammation with the acute inflammatory score (AIS) (on the basis of mucosal ulceration, edema, and quantity and depth of neutrophilic infiltration) and the degree of fibrostenosis was performed at each site, and results were compared with MR imaging features.

The authors found that increasing mural thickness, high mural signal intensity on fat-saturated T2-weighted images and a layered pattern of enhancement are histologically validated as MR imaging features of acute inflammation.