Oral 2.5% Mannitol-Enhanced SICUS for Small Bowel Inflammatory Disease: A Surgical-Validated Comparative Study with MRE

Objective: This study aimed to evaluate the diagnostic value of Small Intestine Contrast Ultrasonography (SICUS) using oral 2.5% mannitol for detecting Small Bowel Inflammatory Disease (SBID), and to compare its efficacy with Magnetic Resonance Enterography (MRE). Methods: Fifty-seven patients with pathologically confirmed SBID who underwent both SICUS and MRE before surgery were retrospectively analyzed. The sensitivity, specificity, and agreement with surgical findings were calculated for each modality in detecting 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 in detecting strictures (87.0% vs. 83.3%) and fistulas (82.8% vs. 65.5%), with strong consistency with surgical findings (κ = 0.83 for fistulas). The sensitivity for detecting abscesses was 81.8% for both modalities. SICUS had 100% specificity in all complications. Its advantages include real-time dynamic imaging, high resolution, reduced interference from intestinal gas, and better accessibility in primary care settings. Conclusions: SICUS is a reliable, non-invasive, and cost-effective imaging method for evaluating SBID and its complications. It provides diagnostic performance comparable or superior to MRE, particularly in detecting strictures and fistulas. SICUS is especially valuable for patients requiring repeated assessments or those who cannot undergo MRE, offering a practical alternative in clinical practice.