Reliability of Intestinal Ultrasound for Evaluating Crohn's Disease Activity Using Point-of-care and Central Reading

Intestinal ultrasound (IUS) is increasingly used to assess Crohn's disease (CD) activity in clinical practice. However, application in clinical trials has been limited by heterogeneous scoring methods and concerns about reliability. We aimed to determine the inter- and intra-rater reliability of locally and centrally read IUS parameters for evaluating CD using prospectively performed scans.

Twenty-four participants with CD and 6 gastroenterologists participated in a 2-day workshop where each participant underwent 6 IUS scans in total. Eight IUS parameters (bowel wall thickness [BWT], bowel wall stratification [BWS], color Doppler signal [CDS], inflammatory mesenteric fat [i-fat], submucosal prominence, submucosal layer thickness, haustra coli/peristalsis, and affected segment length) and an overall measure of sonographic disease activity were blindly assessed by the 6 local readers and 4 central gastroenterologist-sonographers. Reliability was quantified using intraclass correlation coefficients (ICCs). Institutional review board approval was granted for this study (12938).

Five IUS parameters demonstrated at least moderate (ICC ≥0.41) inter- and intra-rater reliability when local and central reading was performed (BWT, CDS, i-fat, submucosal prominence, and affected segment length). Reliability was generally better with central, in distinction to local, reading. ICCs for BWS and i-fat were highest when evaluated as binary outcomes. Sensitivity analyses demonstrated that IUS parameters are most reliable when evaluated in the worst affected segment. Fair reliability was observed when local readers identified the worst affected segment.

Local and central reading of IUS demonstrated at least moderate inter- and intra-rater reliability for several parameters. This study supports refining existing activity indices and incorporating IUS central reading into clinical trials.