['Quantitative hepatobiliary scintigraphy (QHBS) is a valuable method for the detection of a low-grade biliary obstruction in patients with suspected sphincter of Oddi (SO) dysfunction (SOD), though the relatively low specificity of this noninvasive test has been criticized. The aim of the present study was a critical assessment of the diagnostic value of glyceryl trinitrate-augmented QHBS in patients with suspected SOD.', 'Glyceryl trinitrate-augmented QHBS and endoscopic retrograde cholangiopancreatography (ERCP) was performed on 27 cholecystectomized patients with suspected SOD.', 'In 14 patients the ERCP depicted organic causes of biliary obstruction (choledocholithasis, juxtapapillary diverticulum, Vater papilla adenoma and common bile duct stenosis). In 12 of the 13 patients with inconclusive ERCP, endoscopic SO manometry demonstrated an elevated SO basal pressure. In patients with manometrically confirmed SOD, glyceryl trinitrate administration significantly increased the radioactive bile transit into the duodenum and normalized the QHBS parameters. In contrast, the 14 patients with an organic biliary obstruction glyceryl trinitrate administration had no effect on the transpapillary bile flow.'] Is scintigraphic sign of functional biliary obstruction pathognomic for sphincter of Oddi dysfunction?