Given the presence of gallbladder calculi and the dilated biliary tree, it is possible that a stone had passed prior to imaging. The sludge/debris seen in the distal CBD on the MRI was likely contributing to the obstruction since it was absent on the ERCP and the amount of biliary dilatation had decreased on the ERCP as well. Due to the potential of further episodes, the patient progressed to an outpatient cholecystectomy.