Biliary and pancreatic ductal dilation in patients on methadone maintenance therapy

Abstract

Purpose: To determine whether the diameter of intrahepatic and extrahepatic bile ducts and pancreatic ducts in patients on methadone maintenance therapy is increased when compared with control subjects. Methods: Between January 1, 2000 and March 15, 2013, a total of 97 patients (mean age 49.9, range 22–79, 65 male, 32 female) were identified who were receiving chronic methadone maintenance therapy (MMT) when they underwent imaging with abdominal MRI or a contrast-enhanced abdominopelvic CT. A group of 97 consecutive non-MMT control patients (mean age 51.4, range 21–86, 45 male, 52 female) who underwent imaging with abdominal MRI or contrast-enhanced abdominopelvic CT were identified. Patients with known pancreaticobiliary pathology that may confound biliary ductal measurements were excluded. Blinded interpretation was performed, documenting the diameters of the intrahepatic and extrahepatic bile ducts and pancreatic ducts. Descriptive statistics were performed. Results: Patients on MMT demonstrated increased bile duct diameter, with an average increase in duct diameter of 2.39 mm for the common bile duct (p < 0.001; 95% CI 1.88–2.90 mm), 1.43 mm for the intrahepatic bile ducts (p < 0.001; 95% CI 1.12–1.74 mm), and 0.90 mm for the pancreatic duct (p < 0.001; 95% CI 0.64–1.16 mm). No statistically significant correlation was found between ductal diameters and the daily dose of methadone. Conclusion: Patients on methadone maintenance therapy demonstrate significantly increased intra- and extrahepatic bile duct and pancreatic duct diameter when compared with controls. There was no correlation between the dose of methadone and ductal diameter.