Purpose or Case Report: Inflammatory bowel disease (IBD), including Crohn disease, is a cause of significant morbidity in the pediatric population. Perirectal disease is a Crohn related complication affecting as many as 62% of children. Magnetic resonance enterography (MRE) is being increasingly utilized in characterizing the extent of IBD. Dedicated perirectal disease imaging, such as a T2 SPACE, requires an additional 10-15 minutes of imaging time on an already time constrained modality. The goal of our study was to determine the best imaging protocol for patients without clinically suspicious perirectal disease based on the incidence in this population.
Methods & Materials: A retrospective chart review on patients up to 22 years of age who underwent an MRE examination between 1/2015 and 9/2017 for IBD were included in our study. A single reviewer evaluated all included patients’ electronic medical records looking for documented clinical suspicion or colonoscopy/pathology findings of perirectal disease prior to MRE. Patients with prior history of perirectal disease or who had clinically suspected perirectal disease by the treating gastrointestinal physician were excluded. All patients in our study population received dedicated perirectal sequences in addition to the conventional MRE sequences. The study population was evaluated for presence of perirectal disease on MRE. Local institutional review board was approved for this study.
Results: A total of 301 patients had MRE for IBD during our two year time frame. Forty-two patients were excluded due to prior clinical suspicion of perirectal disease, yielding 267 patients in our total population. Fourteen patients (5%) had MRE findings of perirectal disease, five (35%) were found to have perirectal abscess and seven (50%) had a perirectal fistula or fistulous tract.
Conclusions: Our study found a 5% incidence rate of perirectal disease in IBD patients without clinical suspicion of perirectal disease. Thus, radiologists need to be aware of this population to add on perirectal sequences where needed to conventional MRE examinations. However, it is an inefficient use of resources to routinely perform perirectal sequences on this group of patients.