Combined with other modifications, including thin collimation, multiplanar reconstruction, and IV contrast, this protocol maximizes the technique to depict inflammatory changes in the small bowel related to CD [20,22,23]. Although the diagnostic performance is excellent (see below), the need for repeated examinations over time makes this a less attractive choice in this clinical variant. The overall diagnostic performance for CT enterography is excellent. When an endoscopic standard is utilized, sensitivity for CD ranges from 75% to 90%, with a specificity of >90% [24-27]. The diagnosis of acute inflammation is made through visualization of thickened small bowel with mural stratification as well as extraenteric processes including engorged vasa recti/vasculature and surrounding inflammatory stranding [25,26,32-34]. Because of an excellent performance profile, CT enterography is able to assess for mucosal healing similar to MR enterography to help guide therapy [109]. One series (n = 63) demonstrated that CT enterography was able to detect wall changes, and influenced the treatment of CD patients [110]. However, regarding strictures, CT enterography has been considered poor in its ability to distinguish between active and fibrotic contributions to the stricture based on the presence or absence of above-mentioned findings (ie, mural hyper enhancement, thickening, engorged vasa recta, surrounding soft tissue thickening, etc) [108]. 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].
Crohn Disease. Combined with other modifications, including thin collimation, multiplanar reconstruction, and IV contrast, this protocol maximizes the technique to depict inflammatory changes in the small bowel related to CD [20,22,23]. Although the diagnostic performance is excellent (see below), the need for repeated examinations over time makes this a less attractive choice in this clinical variant. The overall diagnostic performance for CT enterography is excellent. When an endoscopic standard is utilized, sensitivity for CD ranges from 75% to 90%, with a specificity of >90% [24-27]. The diagnosis of acute inflammation is made through visualization of thickened small bowel with mural stratification as well as extraenteric processes including engorged vasa recti/vasculature and surrounding inflammatory stranding [25,26,32-34]. Because of an excellent performance profile, CT enterography is able to assess for mucosal healing similar to MR enterography to help guide therapy [109]. One series (n = 63) demonstrated that CT enterography was able to detect wall changes, and influenced the treatment of CD patients [110]. However, regarding strictures, CT enterography has been considered poor in its ability to distinguish between active and fibrotic contributions to the stricture based on the presence or absence of above-mentioned findings (ie, mural hyper enhancement, thickening, engorged vasa recta, surrounding soft tissue thickening, etc) [108]. 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].