Impact of Magnetic Resonance Imaging in Management of Pediatric Crohn's Disease

Abstract

Crohn's disease (CD) is a chronic illness and radiographic evaluation is frequently used. Consequently, pediatric patients with CD who are diagnosed in childhood are at risk for high levels of radiation exposure during their lifetimes. We sought to evaluate the impact of magnetic resonance enterography (MRE) in management of pediatric patients with known or suspected Crohn's disease. A retrospective review of patients with known or suspected CD who underwent MRE for new onset of symptoms was conducted. All demographic data, clinical history, and results of all radiographic, endoscopic, and pathology studies were recorded. Twenty-eight patients with known or suspected CD underwent 31 MRE examinations. MRE showed active disease in 16 (52%), fistula or abscess in seven (22%), and no evidence of active disease in eight (26%). Sixty-five per cent of patients underwent MRE with no other radiation-based imaging used. Surgical intervention was deemed necessary after the MRE in 16 per cent. In all cases, surgical findings were consistent with MRE results. Nearly 60 per cent of patients with CD are managed based on the findings of MRE without additional radiographic evaluation. Based on the results of this retrospective study, we propose a clinical pathway for use of MRE in patients with known or suspected CD with new onset of symptoms.

Utility of MR enterography and ultrasound for the investigation of small bowel Crohn's disease

“…Technological advances in sonographic equipment have been pivotal in establishing sonography for assessment of CD. Specifically, the high spatial resolution of probe technology has facilitated detailed luminal and extraluminal assessment, as well as providing the ability to interrogate the bowel in real time, setting it apart from other investigations, including MRE . Nevertheless, it is well recognized that complete enteric examination, especially of deeper pelvic loops, may not always be possible by sonography and visualization may be limited by luminal gas and body habitus .…”

“…Patient preparation usually necessitates a 4–6‐hour fast, which reduces luminal gas. No specific oral preparation is required for routine SBUS, and administration of IV contrast is rarely performed …”

“…A combination of convex and linear array probes are employed in a systematic manner to cover the entire abdomen and pelvis, to ensure as far as possible that the whole bowel length has been interrogated. Lower‐frequency (3.5–5 MHz) probes provide a panoramic view, particularly useful in obese patients and for evaluating the sigmoid/rectum via the window of a full bladder . Higher‐frequency (up to 18 MHz) probes are essential for high‐resolution visualization of bowel wall to reveal the well‐described five‐layer pattern (Fig.…”

“…Higher‐frequency (up to 18 MHz) probes are essential for high‐resolution visualization of bowel wall to reveal the well‐described five‐layer pattern (Fig. ); an inner hyperechoic layer represents the interface between the mucosa and the bowel lumen; a hypoechoic layer represents the deep mucosa; a second hyperechoic layer, the submucosa; a second hypoechoic layer, the musclaris propria; and the final outer hyperechoic layer the serosa and the serosal fat, along with the underlying mural vascularization . Visualization quality depends on both operator and patient; the ileocecal region, sigmoid, ascending, and descending colon are amenable to accurate visualization.…”

“…The ileum and jejunum can be difficult to assess in their entirety due to overlying bowel loops and a deep pelvic location, whereas visualization of transverse colon is sometimes challenging because of its variable position. Finally, the rectum is often inaccessible due to its deep posterior pelvic location …”