More than half of patients with Crohn disease will develop strictures. Strictures are areas of bowel luminal narrowing composed of a combination of inflammatory cells, muscular hypertrophy, and fibrosis. Most patients with strictures eventually require endoscopic or surgical intervention. This article reviews small bowel Crohn disease stricture histopathology, current imaging definitions and challenges, and stricture management. Current imaging-based stricture definitions use different criteria and do not recognize strictures without upstream dilation nor failed endoscopic passage. This consensus was endorsed by the Society of Abdominal Radiology and developed by the Society of Abdominal Radiology Inflammatory Bowel Disease Disease Focused Panel as well as gastroenterology and pathology experts in Crohn disease strictures. Updated imaging stricture definitions and recommendations are presented. Most importantly, the panel now defines a Crohn disease small bowel stricture using a threshold small bowel dilation of 2.5 cm (rather than 3.0 cm) and incorporates failed endoscopic passage, even when there is no associated bowel dilation at CT or MR enterography. With these updated imaging stricture definitions, it is hoped that patients with Crohn disease may benefit from more timely stricture identification and management.
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