Routine MRCP in the management of patients with gallbladder stones awaiting cholecystectomy: a single-centre experience

Abstract Objectives To assess the frequency of choledocolithiasis and the role of preoperative laboratory findings, ultrasound (US) and magnetic resonance cholangio-pancreatography (MRCP) in the detection of choledocolithiasis in patients with gallbladder stones awaiting cholecystectomy. Methods A consecutive sample of 104 patients underwent MRCP prior to cholecystectomy. The patients were classified into different groups on the basis of the risk of choledocolithiasis. A specialised doctor with more 10 years of experience performed the US interpretation and a radiologist performed the MRCP interpretation blinded to US or aspartate aminotransferase (AST)/alanine aminotransferase (ALT)/alkaline phosphatase (ALP) results. A chi-square (χ2) test was performed to assess the statistical significance of differences in the frequency of choledocolithiasis based on laboratory findings, choledocal diameter on US and group risk. Results MRCP showed calculi in 7 out of 104 patients (6.7%), with no statistically significant differences between the high/moderate risk and low/no risk groups and between the patients with normal and altered laboratory findings or choledocal diameter on preoperative US. The sensitivity and specificity of AST/ALT [positive predictive value (PPV): 12%; negative predictive value (NPV): 94%], ALP (PPV: 7%; NPV: 94%), total serum bilirubin (PPV: 6%; NPV: 93%) and choledocal diameter (PPV: 20%; NPV: 94%) were, respectively, 28.6 and 94.8%, 85.7 and 17.5%, 14.3 and 93.8%, and 14.3 and 95.9%. Conclusions MRCP is a reliable evaluation for the detection of common bile duct (CBD) stones, reducing the misdiagnosis of retained choledocholithiasis with normal biochemical predictors and US examination. Main messages • MRCP is a non-invasive method for the detection of CBD stones. • Preoperative MRCP reduces the misdiagnosis of retained choledocholithiasis. • Detection of choledocholithiasis is mandatory prior to cholecystectomy to avoid surgical morbidit