New consensus guidelines, appeared in Gastroenterology, aim to standardize the use of computed tomography enterography (CTE) and magnetic resonance enterography (MRE) in Crohn’s disease (CD) patients with small-bowel disease.
CTE and MRE can provide information that is not available through clinical or endoscopic exams, Dr. David Bruining of the Mayo Clinic in Rochester, Minnesota, and his colleagues on the Society for Abdominal Radiology’s Crohn’s Disease-Focused Panel, noted.
The Society of Abdominal Radiology (SAR) has issued standards for technical performance of CTE and MRE, they add, and European radiology societies have also issued recommendations on the use of the imaging tests in inflammatory bowel disease patients.
“To date, however,” the authors write, “there are no agreed-upon expectations for structures that should be evaluated at cross-sectional enterography, no standardized nomenclature for describing imaging findings in Crohn’s disease, no guidance for how to describe severity and burden of different Crohn’s disease imaging findings to best guide medical and surgical management, and no consensus between U.S. gastroenterology and radiology societies on when these tests should be performed.”
The panel has now issued the following recommendations on the use of CTE and MRE:
- Small bowel disease is likely in patients with known CD, mural hyperenhancement and wall thickening, or if inflammation is asymmetrical or accompanies typical penetrating complications of CD.
- The number of involved bowel segments and location should be reported by radiologists, as well as the length and degree of upstream dilation of Crohn’s strictures, to help gastroenterologists and surgeons determine the best therapeutic plan.
- Radiologists should state if mural inflammation is present when describing areas with stricture or penetrating disease.
- Cross-sectional enterography should be performed at CD diagnosis.
- Consider cross-sectional enterography for disease monitoring in patients with small-bowel disease or penetrating complications.
- While a dedicated pelvic MR is needed in patients with perianal disease, all CTEs and MREs should also include imaging of the anus.
- Radiologists should comment on and describe intramural T2 hyperintensity, restricted diffusion, peri-enteric stranding, wall thickness and mural ulcerations seen on imaging because they typically correlate with disease severity.
- MRE is preferred over CTE to estimate response to medical treatment in patients with asymptomatic disease.
- Non-contrast MRE with T2-weighted and diffusion-weighted imaging is an “acceptable alternative” when intravenous contrast agents cannot be used.
- Radiologists should evaluate CTE and MRE examinations for signs of mesenteric venous thrombosis, occlusions or small-bowel varices.
“A shared approach for linking specific imaging findings to clinically useful impressions can be used to better guide therapeutic decision making in the short term, and improve our understanding of the natural history of long-term complications of Crohn’s disease,” the authors concluded.