Unveiling Hidden Diagnoses: The Prevalence and Clinical Impact of Extra-biliary Findings on Magnetic Resonance Cholangiopancreatography

Background Magnetic resonance cholangiopancreatography (MRCP) is being increasingly employed for evaluating the biliary tree. This imaging technique has the potential to uncover extra-biliary abnormalities that may necessitate additional urgent investigations. The primary aim of this study was to determine the prevalence of extra-biliary findings on MRCPs. A secondary aim was to evaluate the subsequent need for further investigations and their outcomes. Methods This retrospective cohort study reviewed consecutive MRCPs performed on adult patients at a single centre between November 2020 and September 2022. Patient demographics, MRCP indications, results including extra-biliary findings, and subsequent investigations and outcomes were analysed using electronic case notes. Results A total of 1,018 MRCPs were included in this study; 617 (60.6%) were for female patients, and the median age was 64 years (IQR: 50-75). Specifically, 648 (63.7%) were inpatient, 418 (41.1%) were urgent, 592 (58.2%) had at least one extra-biliary finding, and 96 (9.4%) required urgent follow-up investigations, with 26 (2.6%) new diagnoses of malignancy. Additionally, 213 (20.9%) had renal cysts, 118 (11.6%) had hepatic cysts, 69 (6.7%) had pancreatic cysts, 28 (2.8%) had liver cirrhosis, 23 (2.3%) had peripancreatic collection(s), 42 (4.1%) had a hiatus hernia, 79 (7.8%) had pleural effusion(s), 46 (4.5%) had splenomegaly, and 2.6% (n=26) had identified diverticular disease. Conclusions Over half of the MRCPs performed identified at least one extra-biliary finding. Among those requiring urgent follow-up, over 25% led to newly diagnosed malignancies. This underscores MRCP's high sensitivity, extending beyond biliary conditions to effectively detect extra-biliary pathologies. Our findings support consideration of adopting a structured proforma for reporting MRCPs.