MR enterography evaluation of Crohns disease - terminal ileitis

Case Discussion

Typical findings of terminal ileitis related to Crohns disease, diagnosed with MR Enterography. Each sequence can offer insight that help you confidently evaluate inflammatory bowel disease, and work together to give a consistent picture of the pathology. Practically, multiple sequences is often helpful as motion degradation may impact your ability to detect inflammation. Additionally, the bowel may be contracting one sequence, so the multiplicity over time and CINE images will help to be confident about "true" findings. The following are my suggestions when reading these studies: 

• Cor SSFSE - fast sequence that usually turns out great even if the patient moves; good for getting a "lay of the land" and planning your review of the images (e.g. which areas need carefully interrogation), screening all non GI structures including the solid organs and scanning the bowel wall for areas that will want to interrogate further 
• Cor CINE - this is your SBFT-equivalent, and allows you to corroborate any suspected areas of inflammation, stricture, or fistula with impaired mobility; this sequence can also help draw your attention to certain areas that you may overlook on the other sequences
• Cor T1+ - these post-contrast images often turn out a bit blurry or have artifacts, but they are a good side-by-side comparison where you are looking for abnormal enhancement and thickening of the bowel, as well as vasa recta
• Ax T2FS - these images help you look for edema within the mesentery and bowel wall, which indicates active inflammation; these work together with the Axial T1+ to complete the survey images of the entire abdomen and pelvis
• Ax T1+ - these images provide another look at areas of wall thickening to evaluate the extent of enhancement (including the surrounding mesentery); as well as a general post-contrast survey of the entire abdomen and pelvis 

Generally speaking, CT enterography is better for evaluating abdominal fistulous disease which can be difficult to sort out on MRI, but MRI is far superior for perianal fistulas.