Evaluating the use of MRCP requests for the investigation of common bile duct stones: an audit at a district general hospital

Introduction: AUGIS guidelines recommends magnetic resonance cholangiopancreatography (MRCP) for patients with highest risk for common bile duct stones (CBDS). Patients with either normal liver function tests (LFTs) or normal bile duct diameter on initial investigations can proceed to laparoscopic cholecystectomy (LC) with intra-operative cholangiogram or laparoscopic bile duct exploration without MRCP and this is considered a cost-effective and safe approach. Methods: Data was collected retrospectively for patients who had a MRCP for suspected CBDS in NHS Lanarkshire between January and February 2025. Electronic records were reviewed for LFTs and abdominal ultrasound findings at the time of MRCP request. Patients were then stratified to whether their requests met AUGIS guidelines for pre-LC MRCP. Results: Among 52 requests for suspected CBDS, only 15 (29%) had both abnormal LFTs or dilated bile duct to warrant an MRCP. 43 (82.7%) of requests were negative for CBDS, 8 (15.4%) were positive and 1 (2%) found a neoplasm. The median time to MRCP was 21.5 days (2-199) and among 8 patients who had LC during this period, median time to LC was 32 days (9-49). Discussion: The majority of MRCP requests do not meet AUGIS guidelines for CBD stones and most are negative for CBDS. There are currently significant waiting times due to pressures on limited MRI slots in this district general hospital. Prioritising MRCP requests for highest risk patients for CBDS could save costs and allow timely interventions for patients with acute gallstone disease.