Correlation between small intestinal contrast ultrasonography and magnetic resonance imaging scoring systems in Crohn's disease.

Abstract

The use of intestinal ultrasound (IUS) in Crohn's disease (CD) is increasing. However, the performance of established IUS scoring systems in the setting of small intestinal contrast ultrasonography (SICUS) remains underexplored. This study aimed to evaluate the correlation between SICUS and magnetic resonance imaging (MRI) scoring systems. This study included 504 paired SICUS and MRI assessments performed concurrently in patients with CD. Spearman's correlation was used to assess the relationship between SICUS scores, simplified magnetic resonance index of activity (sMaRIA), CD activity index (CDAI), and inflammatory biomarkers. Receiver operating characteristic (ROC) analysis was used to evaluate the diagnostic performance of SICUS scores against sMaRIA thresholds. DeLong's test was used to compare discriminative ability across SICUS scores. All SICUS scores exhibited significant positive correlations with the sMaRIA (p < 0.001), with the international bowel ultrasound segmental activity score (IBUS-SAS) ranking the highest (r = 0.824). Both sMaRIA and SICUS scores correlated significantly with CDAI and inflammatory biomarkers (p < 0.001). For severe MRI-defined activity, ROC analysis showed that IBUS-SAS achieved the highest area under the curve (AUC, 0.95; 95% confidence interval [CI]: 0.93-0.97), significantly outperforming other scores, with 90.3% sensitivity and 89.3% specificity, at a cut-off of 72.60. All SICUS scores demonstrated similar AUCs for MRI-defined disease activity, with IBUS-SAS offering a slight, non-significant advantage. SICUS-derived scores achieved diagnostic performance comparable to MRI in assessing CD activity and severity. Notably, the IBUS-SAS demonstrated superior performance, indicating its potential as an optimal modality for long-term monitoring. Question Does SICUS provide diagnostic performance comparable to MRI, and can it serve as an alternative for diagnosing, assessing, and monitoring CD? Findings SICUS demonstrates diagnostic efficacy comparable to MRI in assessing CD activity and severity, correlates significantly with CDAI and inflammatory biomarkers, and exhibits favorable performance characteristics. Clinical relevance Demonstrating diagnostic efficacy equivalent to MRI and offering practical advantages in accessibility, cost-effectiveness, and safety, SICUS represents a reliable modality for longitudinal monitoring in CD, either as an alternative or adjunct to MRI.