Oral 2.5% mannitol Small Intestine Contrast Ultrasound for small bowel inflammatory disease: A Surgical-Validated Comparative Study with Magnetic Resonance Enterography

Objective This study aimed to evaluate the diagnostic performance of Small Intestine Contrast Ultrasound (SICUS) with oral 2.5% mannitol in detecting small bowel inflammatory disease (SBID), and to compare its efficacy with that of Magnetic Resonance Enterography (MRE). Methods A retrospective analysis was conducted in 57 patients with pathologically confirmed SBID who underwent both SICUS and MRE prior to surgery. The sensitivity, specificity, and concordance with surgical findings were calculated for each modality in diagnosing SBID and its complications, including strictures, fistulas, and abscesses. Results Both SICUS and MRE achieved a detection rate of 96.5% for SBID. SICUS showed higher sensitivity than MRE for identifying strictures (87.0% vs. 83.3%) and fistulas (82.8% vs. 65.5%), with strong consistency with surgical findings (κ = 0.83 for fistulas). For detecting abscesses, the sensitivity was 81.8% for both modalities. Notably, SICUS achieved 100% specificity for all complications. Additional advantages of SICUS include real-time dynamic evaluation, high spatial resolution, reduced interference from intestinal gas, and greater accessibility in primary care settings. Conclusions SICUS is a reliable, non-invasive, and cost-effective imaging technique for evaluating SBID and its complications. It provides diagnostic performance comparable to or exceeding that of MRE, particularly for strictures and fistulas. Given its repeatability and suitability for patients unable to undergo MRE, SICUS represents a practical alternative in clinical practice.