P482 Diagnostic accuracy of contrast-enhanced ultrasound for fibrotic strictures of Crohn’s disease: a systematic review and meta-analysis of individual participant data

Abstract

Abstract Background Crohn's disease (CD) often leads to the development of intestinal strictures, requiring effective differentiation between inflammatory and fibrotic for the optimal treatment strategies. Despite recent advances in drug development targeting fibrosis, current evaluation methods remain insufficient. Contrast-enhanced ultrasound (CEUS) is a promising modality for assessing vascularity and inflammation, yet its accuracy in fibrosis detection needs more validation. Methods A systematic review and meta-analysis were conducted using IPD to determine the diagnostic accuracy of CEUS in identifying intestinal fibrosis in CD. Our search included databases such as MEDLINE, EMBASE, and Web of Science up until March 23, 2023. Inclusion criteria required a confirmed diagnosis of CD and studies that evaluated the accuracy of CEUS parameters, including total area under the curve (AUC), wash-in AUC, wash-out AUC, peak enhancement, wash-in perfusion index, wash-in rate, wash-out rate, rise time, fall time, and mean transit time related to fibrosis in CD (Figure 1 (A)). The quality of included studies was assessed using the QUADAS-2 tool, with each study mandatorily using surgical specimen pathology as a reference standard in at least one instance. Results Our qualitative synthesis included eight studies encompassing 306 patients. These studies were generally assessed to have a high risk of bias. It is important to note that while peak enhancement and AUC were frequently examined across studies, neither parameter had established absolute cutoff values for the diagnosis of fibrosis. From the three studies where IPD was available, detailed data from 80 patients were included in the meta-analysis (colon n=11 and small bowel n= 69). Among them, 54 underwent surgical intervention with fibrosis being confirmed in 31. The highest diagnostic accuracy was observed for total AUC and wash-in AUC, with pooled sensitivity and specificity for predicting fibrosis at 0.86 (95% CI, 0.59–0.97) and 0.25 (95% CI, 0.03–0.76), respectively (Figure 1 (B)). Conclusion This meta-analysis with IPD pioneers the exclusive evaluation of CEUS for fibrotic strictures in CD. It reveals a significant risk of bias in the primary research and a notable absence of consensus on the CEUS parameters' threshold values for distinguishing fibrosis from inflammation. The observed low specificity highlights the need for innovative strategies in future research, such as integrating CEUS with techniques like elastography, to enhance the precision of fibrosis detection in CD. PROSPERO 2020 CRD42020214472. https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42020214472