Magnetic resonance cholangiopancreatography in acute cholecystitis: Is it necessary for patients with normal common bile duct diameter?

Aim Investigating concurrent choledocholithiasis in patients with acute cholecystitis (AC) and normal common bile duct (CBD) diameter on ultrasound by performing magnetic resonance cholangiopancreatography (MRCP) can be challenging. This study aims to determine the conditions that necessitate MRCP before surgery and its potential impact on the course of treatment for these patients. Patients and methods We included 100 patients with AC and normal CBD diameter who were admitted to Shahid Modarres Hospital from September 2019 to September 2022. Patients with elevated levels of any liver serum markers above the upper limit of normal underwent MRCP. Results The MRCP results were positive in 45.16% of cases and altered the type of treatment in 35.48% of them. The findings indicated that direct [area under the curve (AUC) = 0.782; 95% confidence interval (CI) 0.597–0.909] and total bilirubin (AUC = 0.697; 95% CI 0.507–0.849) were significantly effective in predicting the positive findings for concurrent CBD stone or Mirizzi's syndrome on MRCP. The optimal cutoff values for direct and total bilirubin were found to be above 1.02 and 2.19 mg/dL. Concerning the alteration of treatment approaches, direct bilirubin demonstrated predictive value (P = .014) at levels above 1.02 mg/dL. Conclusions In cases of AC with a normal CBD diameter on ultrasound and mild elevations in liver function parameters, including total and direct bilirubin, it is not routinely necessary to perform MRCP. However, if these laboratory values exceed a certain threshold, MRCP is recommended as it may reveal alternative diagnoses that could alter the clinical management.