CT enterography is more sensitive for bowel changes related to CD than standard CT given the oral contrast optimization. However, the findings of CD in an acute flare are often not subtle and can be seen at standard CT. In addition, the complications including abscess or fistula formation may be easier seen at standard CT with positive oral contrast. 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, and IV contrast is given. There have been few studies evaluating performance in recent years. 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]. In this specific variant, MR enteroclysis may be limited dependent on the clinical acuity or severity of presentation. With a significant acute flare or complication, the patient would poorly tolerate MR enteroclysis because of the marked demands on the patient related to the placement of the nasoduodenal tube and need for active infusion of oral contrast. Here, the risks outweigh the added benefits of optimized bowel visualization, and this imaging choice should be avoided when acutely ill. In addition, patients are likely unable to hold still, leading to increased artifact and poorer image quality. If, however, the patient is relatively asymptomatic, MR enteroclysis may be an appropriate option with excellent diagnostic performance. MR Enterography MR enterography combines contrast-enhanced MRI scanning using fast imaging techniques with an enterography protocol to optimize bowel distension [38].
Crohn Disease. CT enterography is more sensitive for bowel changes related to CD than standard CT given the oral contrast optimization. However, the findings of CD in an acute flare are often not subtle and can be seen at standard CT. In addition, the complications including abscess or fistula formation may be easier seen at standard CT with positive oral contrast. 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, and IV contrast is given. There have been few studies evaluating performance in recent years. 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]. In this specific variant, MR enteroclysis may be limited dependent on the clinical acuity or severity of presentation. With a significant acute flare or complication, the patient would poorly tolerate MR enteroclysis because of the marked demands on the patient related to the placement of the nasoduodenal tube and need for active infusion of oral contrast. Here, the risks outweigh the added benefits of optimized bowel visualization, and this imaging choice should be avoided when acutely ill. In addition, patients are likely unable to hold still, leading to increased artifact and poorer image quality. If, however, the patient is relatively asymptomatic, MR enteroclysis may be an appropriate option with excellent diagnostic performance. MR Enterography MR enterography combines contrast-enhanced MRI scanning using fast imaging techniques with an enterography protocol to optimize bowel distension [38].