Pediatric MR Enterography: Technique and Approach to Interpretation—How We Do It

Abstract

Magnetic resonance (MR) enterography is an increasingly important pediatric imaging modality that is most often used to evaluate inflammatory bowel disease ( IBD inflammatory bowel disease ), while sparing children and adolescents from potential risks of ionizing radiation exposure. MR enterography allows for evaluation of the bowel lumen and wall, adjacent mesentery and soft tissues, as well as a variety of extraintestinal abdominopelvic IBD inflammatory bowel disease manifestations. While MR enterography can be used to initially confirm the diagnosis of IBD inflammatory bowel disease , particularly small bowel Crohn disease, it has also proven useful in assessing the degree inflammatory activity over time, serving as a radiologic biomarker for response to medical therapy, and identifying a variety of disease-related complications, including strictures, fistulae, and abscesses. The purpose of this review article is to provide radiologists with a systematic approach for MR enterography review and interpretation in children and adolescents with known or suspected of having IBD inflammatory bowel disease and to illustrate both common and infrequent but important imaging findings. Additionally, the authors will present their well-established and clinically successful pediatric MR enterography protocol, up-to-date clinical indications for MR enterography, and briefly mention the role of MR enterography in assessing non- IBD inflammatory bowel disease abnormalities affecting the bowel. Online supplemental material is available for this article .

Role of imaging in the evaluation of inflammatory bowel disease: How much is too much?

“…Patients typically drink 12 L of a hyper osmolar oral contrast material to distend the bowel lumen, which can be difficult for younger patients and is often not well tolerated. Intra venous gadolinium contrast and spasmolytic medications such as glucagon are often administered during the study [28,29] . The imaging procedure generally takes 12 h to complete, and patients must comply with instructions to hold their breath intermittently.…”

Current tecniques and new perpectives research of magnetic resonance enterography in pediatric Crohn’s disease

“…These tracts are commonly recognized on singleshot FSE, balanced SSFE and fat-saturated T2-weighted FSE pulse images (with a sensitivity ranges from 83.3% to 84.4% and specificity of 100% [33,56,66,70] ) as linear or stellate hypointense or hyperintense (if fluidfilled) abnormalities and also commonly enhance on post-contrast T1-weighted images [3] . Diagnostic advanced in CD: DWI, Perfusion, Motility Imaging, Magnetic Resonance Spectroscopy (MRS), and PET-MRI.…”

“…The economic effects of pediatric and adult CD are staggering and are estimated to be between $10.9 billion and $15.5 billion per year in the United Sates alone [3] . Diagnosis and follow-up of bowel CD in children and adults are typically based on a combination of patient history and physical examination, such as disease activity surveys [e.g., the Pediatric Crohn's Disease Activity Index (CDAI)], laboratory assessment, endoscopy with biopsy, and imaging [4] .…”

“…Traditionally, pediatric CD has been diagnosed and monitored over time by using endoscopy and fluoroscopic endoluminal contrast materialenhanced studies (e.g., upper gastrointestinal series, small bowel followthrough, and contrast enema). Endoscopy with biopsy is considered as gold standard in diagnosis CD in particular in lesions localized in terminal segment of the ileum and for capability of obtaining samples for histopathologic assessment [3] . However endoscopic techniques have some limitations including poor accessibility to remaining part of the small bowel (except for difficult and time-consuming enteroscopy), risk of bowel perforation and limited ability to evaluate extraluminal structures.…”

“…One recent study [25] , explained that the second technique was extremely accurate in detective active inflammation and in the absence of active inflammation, MR enterography showed high precision to detect the mural fibrosis [26] . The progress in MR techniques and the development of new sequences with short exposition time, which are less sensitive to motion artifacts, has enabled acquiring good quality images of abdominal organs in children and currently it is considered the method of choice for the evaluation of CD severity and activity as well as for monitoring treatment effectiveness in children [3] . The recent development of faster pulse sequences, in fact, gives an opportunity to provide a movie cine images [27] .…”