As described with CT enterography, this requires the patient to ingest a large volume of oral contrast in a set time. Additionally, the use of glucagon or prone imaging may help to decrease bowel peristalsis and thus artifact. MR enterography holds excellent test performance characteristics (see below) equivalent to other optimized modalities, such as CT enterography. The ability to diagnose alternative diagnoses may be decreased in cases when a CT-based option may be preferable, depending on the level of patient acuity and ability to hold still. Severely ill patients are less likely to be able to hold still for the duration of MRI examination, leading to increased artifact and poorer image quality. In addition, if ill, the patient may not be able to tolerate the required large volumes of contrast required at MR enterography. MRI Abdomen and Pelvis Standard MRI with a routine protocol (ie, MRI without and with IV contrast and without oral contrast enterography technique) can detect evidence of CD if the patient cannot tolerate large volumes of oral contrast (ie, acutely ill patients). However, the lack of bowel optimization technique decreases evaluation of more subtle findings. One study (n = 100) reported a sensitivity of 50% to 86% and specificity of 93% to 94% for wall thickening [73]. Thus, standard MR may be an option when oral contrast requirements at enterography cannot be tolerated. For CD complications, the diagnostic ability of MRI is similar to standard CT with IV with similar reported sensitivities and specificities in various series [27,40,58,72]. The sensitivity for stenosis/obstruction ranges from 87% to 92% with high specificities; detection performance remains high for abscesses, with sensitivity ranging from 86% to 100%. As with CT, the detection for fistulas is more variable, ranging from 40% to 100%. Because of
Crohn Disease. As described with CT enterography, this requires the patient to ingest a large volume of oral contrast in a set time. Additionally, the use of glucagon or prone imaging may help to decrease bowel peristalsis and thus artifact. MR enterography holds excellent test performance characteristics (see below) equivalent to other optimized modalities, such as CT enterography. The ability to diagnose alternative diagnoses may be decreased in cases when a CT-based option may be preferable, depending on the level of patient acuity and ability to hold still. Severely ill patients are less likely to be able to hold still for the duration of MRI examination, leading to increased artifact and poorer image quality. In addition, if ill, the patient may not be able to tolerate the required large volumes of contrast required at MR enterography. MRI Abdomen and Pelvis Standard MRI with a routine protocol (ie, MRI without and with IV contrast and without oral contrast enterography technique) can detect evidence of CD if the patient cannot tolerate large volumes of oral contrast (ie, acutely ill patients). However, the lack of bowel optimization technique decreases evaluation of more subtle findings. One study (n = 100) reported a sensitivity of 50% to 86% and specificity of 93% to 94% for wall thickening [73]. Thus, standard MR may be an option when oral contrast requirements at enterography cannot be tolerated. For CD complications, the diagnostic ability of MRI is similar to standard CT with IV with similar reported sensitivities and specificities in various series [27,40,58,72]. The sensitivity for stenosis/obstruction ranges from 87% to 92% with high specificities; detection performance remains high for abscesses, with sensitivity ranging from 86% to 100%. As with CT, the detection for fistulas is more variable, ranging from 40% to 100%. Because of