Smarter Scanning: Reducing Unnecessary Magnetic Resonance Cholangiopancreatography (MRCP) in Low-Risk Gallstone...

Background Gallstone disease is a common condition that often requires imaging to exclude choledocholithiasis. Magnetic resonance cholangiopancreatography (MRCP) is a highly accurate but costly scan, increasingly used in low- to moderate-risk patients where its diagnostic yield may be low. Objective This audit evaluated the diagnostic yield of MRCP in low- to moderate-risk gallstone patients and assessed the predictive value of liver function tests (LFTs) and ultrasound (USS) findings to develop a smarter referral approach. Methods A retrospective audit was conducted at a single NHS Trust from January to December 2024. Data on MRCP outcomes, pre-scan LFTs (bilirubin, alkaline phosphatase (ALP)), and USS common bile duct (CBD) diameter were analyzed using chi-squared tests. A composite score (MRCP-RS) combining key predictors was explored to guide smarter MRCP referrals. Results Among 329 MRCPs, 42.2% were normal. Elevated bilirubin and ALP showed no significant association with abnormal MRCPs (p=1.00 and p=0.61). Dilated CBD on USS had limited predictive value (p=0.82). The MRCP-RS composite score demonstrated a trend of increasing abnormal MRCP rates with higher scores but modest discriminative ability. Avoidable normal MRCPs incurred an estimated annual cost of £38,000-65,000. Conclusion Routine use of MRCP in low-risk gallstone patients leads to unnecessary imaging and costs. Neither LFTs nor USS alone is a reliable predictor. A combined approach using a simple composite score may improve referral decisions. Adoption of smarter referral tools and re-audit post-implementation are recommended.