MR Enteroclysis MR enteroclysis is a MR-based examination in which a nasoduodenal tube is placed to allow controlled distention of the small bowel. Typically, biphasic enteral contrast (low signal on T1 and high signal on T2) is infused over time prior to MRI, and IV contrast is given during the MR examination. The technical demands of this more invasive examination are greater but typically allow for better distention of the small bowel compared with oral ingestion with an enterography technique [48]. There have been few studies evaluating performance of this technique in recent years because it is not a widely utilized examination. Although bowel distention of the jejunum is typically less at enterography than with enteroclysis, distention achieved with enterography is considered acceptable [17] and has been more widely utilized compared with MR enteroclysis. As with all imaging modalities, it is difficult to precisely determine the test characteristics in CD exactly because of the lack of a true reference standard. However, the overall diagnostic performance for MR enteroclysis is excellent and at least equivalent to MR enterography [49]. One comparison study between these two modalities demonstrated statistically better detection of superficial mucosal abnormalities over MR enterography but no difference for stenoses and fistulas [50]. Although the bowel optimization at MR enteroclysis allows excellent examination performance, equivalent to the highest-performing modalities, MR enteroclysis is not typically suitable in the acute setting in which the patient is ill. Often, they cannot tolerate the requirements related to placement of the nasoduodenal tube and active infusion of contrast. In addition, the evaluation for alternative diagnoses mimicking CD may be more difficult or limited. MR Enterography MR enterography combines contrast-enhanced MRI scanning using fast imaging techniques with an enterography protocol to optimize bowel distension [38].
Crohn Disease. MR Enteroclysis MR enteroclysis is a MR-based examination in which a nasoduodenal tube is placed to allow controlled distention of the small bowel. Typically, biphasic enteral contrast (low signal on T1 and high signal on T2) is infused over time prior to MRI, and IV contrast is given during the MR examination. The technical demands of this more invasive examination are greater but typically allow for better distention of the small bowel compared with oral ingestion with an enterography technique [48]. There have been few studies evaluating performance of this technique in recent years because it is not a widely utilized examination. Although bowel distention of the jejunum is typically less at enterography than with enteroclysis, distention achieved with enterography is considered acceptable [17] and has been more widely utilized compared with MR enteroclysis. As with all imaging modalities, it is difficult to precisely determine the test characteristics in CD exactly because of the lack of a true reference standard. However, the overall diagnostic performance for MR enteroclysis is excellent and at least equivalent to MR enterography [49]. One comparison study between these two modalities demonstrated statistically better detection of superficial mucosal abnormalities over MR enterography but no difference for stenoses and fistulas [50]. Although the bowel optimization at MR enteroclysis allows excellent examination performance, equivalent to the highest-performing modalities, MR enteroclysis is not typically suitable in the acute setting in which the patient is ill. Often, they cannot tolerate the requirements related to placement of the nasoduodenal tube and active infusion of contrast. In addition, the evaluation for alternative diagnoses mimicking CD may be more difficult or limited. MR Enterography MR enterography combines contrast-enhanced MRI scanning using fast imaging techniques with an enterography protocol to optimize bowel distension [38].