HPB P15 Diagnosis of Choledocholithiasis in Risk-Stratified patients: the benefits of Magnetic Resonance Cholangiopancreatography. - A single centre retrospective cohort study

Abstract

Abstract Background Association of Upper Gastrointestinal Surgeons (AUGIS) guidelines recommend that magnetic resonance cholangiopancreatography (MRCP) should be performed in patients with suspected gallstone disease who have deranged liver function tests (LFTs) and dilated bile ducts on ultrasound scan (USS). Early laparoscopic cholecystectomy (LC) is recommended to reduce complications of gallstone disease. Confirmation of choledocholithiasis helps guide acute management as well as operative planning. The aim of this study was to determine the probability of choledocholithiasis on MRCP of risk stratified patients. Methods A retrospective cohort study of adult patients who underwent MRCP in a single centre was conducted from September 2020 to September 2022. Patients being investigated for non-biliary indications (e.g. hepato-pancreato-biliary malignancies) were excluded. Patient demographics, pre-MRCP peak LFTs, clinical indications and all radiology imaging results were analysed. Patients were risk-stratified based on modified AUGIS guidelines using hyperbilirubinemia and the presence of biliary duct dilation on USS and CT-scans as risk factors. Patients with MRCP proven choledocholithiasis were compared to those without. P value was calculated using chi-square testing. This study was registered with Clinical Quality Project (LanQIP: 14737). Results 1,107 MRCP were identified; 97 were excluded. Median age was 65 years (IQR 50.3-75) and 625 (61.9%) were female. 677 (67%) were inpatient scans and 432 (42. 8%) were urgent. Median time for inpatient scans was 1.1 days (IQR 0.8-2.1). 739 (73.2%) patients had known gallstones. 157 (15.5%) were post-cholecystectomy. 596 (59%) had hyperbilirubinemia and 726 (71.9%) had elevated alkaline phosphatase (ALP). 38.5% of USS and 48.2% of CT scans showed dilated ducts. Overall, 276 (27.3%) MRCPs showed choledocholithiasis. Raised ALP, hyperbilirubinemia, and dilated ducts on preceding imaging were strongly predictive for choledocholithiasis on MRCP (p<0.001). Conclusions Our result are consistent with previously published data. We suggest that AUGIS guidelines should be used to risk stratify patients to maximise the utility of MRCP. If early LC cannot be performed, careful assessment of patient risk factors can guide the need for MRCP to determine the need for interval endoscopic retrograde cholangiopancreatography and aid pre-operative surgical planning. In centres where expertise is available, intra-operative cholangiogram can replace the need for MRCP in low-risk group.