P199. Is contrast-enhanced ultrasound (CE-US) superior to conventional ultrasonography (cUS) for the assessment of small bowel Crohn's disease inflammatory activity, as graded by magnetic resonance enterography (MRI)?
S. Boyer1, E. Guillot2, D. Marion2, G. Boschetti1, P.-J. Valette2, B. Flourié1, S. Nancey1, 1Hospices Civils de Lyon, Lyon-Sud hospital, Gastroenterology, Pierre Benite, France, 2Hospices Civils de Lyon, Lyon-Sud hospital, Radiology, Pierre Benite, France
The role of contrast-enhanced ultrasonography (CE-US) for assessing CD activity remains unclear. AIMS: To compare the performance of CE-US with that of US to detect CD activity assessed by MR-enterography (MRI) taken as the reference.
Thirty-six patients (16F, median age 34 yrs) with small bowel CD were prospectively studied. Clinical disease activity was assessed by the Harvey–Bradshaw Index (HBI). All patients underwent a MRI and also a cUS followed by a CE-US using a microbubble contrast agent (SonoVue®). Disease small bowel activity was assessed by MRI (reference) and patients were graded as inactive, moderately or severely active. Qualitative and quantitative parameters from the sonographic analysis included maximum wall thickness, bowel layer features, contrast intraparietal and transparietal enhancements and time-intensity curves, including the slope of the first ascending tract, the time to the peak enhancement and the area under enhancement curve.
Among the 27 patients in clinical remission (HBI ≤4 points), 15 patients (56%) had evident signs of inflammatory activity on MRI or in CEUS (bowel wall thickness and contrast enhancement). The bowel wall thickness measured by cUS was an accurate parameter (AUC = 0.82) to discriminate patients with an active or inactive CD assessed by MRI. Using a cutoff of 3.5 mm, its sensitivity (Se) and specificity (Spe) to detect an inflammatory activity were 89% and 71%, respectively. There was a positive and significant correlation between wall thickness assessed by cUS and MRI (correlation coefficient r′ = 0.76, p < 0.001) and an excellent overall concordance between CEUS and MRI. The comb sign and contrast enhancement were the best to detect disease activity (overall accuracy 81% and 86%, respectively). Among quantitative data from CEUS after Sonovue®, only the slope of the first ascending tract was significantly correlated with bowel wall thickness measured by MRI (r′ = 0.62; p < 0.001). A slope of the first ascending tract ≤3.2 VI/sec obtained by CEUS allowed, with a good accuracy, to identify an active CD assessed by MRI (AUC = 0.75; Se = 66%; Spe = 83%). Six patients were judged inactive by MRI but had a significant wall thickness by cUS (and could subsequently be misclassified since considered as having an active disease by cUS). After Sonovue®, all had a slope of the first ascending tract ≤3.2 VI/sec suggesting that CEUS may confirm the absence of significant disease activity despite an abnormal wall thickness.
The comb sign, contrast enhancement and slope of the first ascending tract obtained by CEUS are valuable parameters for an accurate detection and quantification of small bowel inflammatory activity in CD.