Abstract
Background and study aims Endoscopic ultrasonography (EUS) is a tool widely used to diagnose bile duct lithiasis. In approximately one out of five patients with positive findings at EUS, sludge is detected in the bile duct instead of stones. The objective of this study was to establish the agreement among endosonographers regarding: 1. presence of common bile duct (CBD) stones, microlithiasis and sludge; and 2. the need for subsequent treatment. Patients and methods 30 EUS videos of patients with an intermediate probability of CBD stones were evaluated by 41 endosonographers. Experience in EUS and endoscopic retrograde cholangiopancreatography, and the endosonographers' type of practices were recorded. Fleiss' kappa statistics were used to quantify the agreement. Associations between levels of experience and both EUS ratings and treatment decisions were investigated using mixed effects models. Results A total of 1230 ratings and treatment decisions were evaluated. The overall agreement on EUS findings was fair (Fleiss' κ 0.32). The agreement on presence of stones was moderate (κ 0.46). For microlithiasis it was fair (κ 0.25) and for sludge it was slight (κ 0.16). In cases with CBD stones there was an almost perfect agreement for the decision to subsequently perform an ERC + ES. In case of presumed microlithiasis or sludge an ERC was opted for in 78 % and 51 % of cases, respectively. Differences in experience and types of practice appear unrelated to the agreement on both EUS findings and the decision for subsequent treatment. Conclusions There is only slight agreement among endosonographers regarding the presence of bile duct sludge. Regarding the need for subsequent treatment of bile duct sludge there is no consensus.