MR enteroclysis imaging of Crohn disease

Magnetic resonance (MR) enteroclysis imaging is emerging as a technique for evaluation of the small bowel in patients with Crohn disease. Administration of 1.5-2 L of isosmotic water solution through a nasojejunal catheter ensures distention of the bowel and facilitates identification of wall abnormalities. True fast imaging with steady-state precession (FISP), half-Fourier acquisition single-shot turbo spin-echo (HASTE), and postgadolinium T1-weighted three-dimensional fast low-angle shot sequences can be employed in a comprehensive and integrated MR enteroclysis examination protocol to overcome specific disadvantages of each of the sequences involved. Superficial abnormalities that are ideally delineated with conventional enteroclysis are not consistently depicted with MR enteroclysis. The characteristic transmural abnormalities of Crohn disease such as bowel wall thickening, linear ulcers, and cobblestoning are accurately shown with MR enteroclysis imaging, especially with the true FISP sequence. MR enteroclysis is comparable to conventional enteroclysis in the detection of the number and extent of involved small bowel segments and in the disclosure of luminal narrowing or prestenotic intestinal dilatation. The clinical utility of MR enteroclysis in Crohn disease has not been fully established. At present, the method may be used for follow-up studies of known disease, estimation of disease activity, and determination of the extramucosal extent and spread of the disease process.