Radionuclide angiography and cholescintigraphy were performed with a bolus injection of technetium-99m disofenin in 65 patients with suspected acute cholecystitis. Acute cholecystitis was surgically confirmed in 23 of 25 cases in which radionuclide angiographic findings were positive (i.e., showed focal increased flow to the gallbladder region) (positive predictive value, 92%). Sensitivity and specificity of radionuclide angiography for detecting acute cholecystitis were 72% and 94% for cholescintigraphy. Three patients with scintigraphically visible gallbladders (at 45 minutes, 2.4 hours, and 4.5 hours) and positive angiograms had severe acute cholecystitis and abscess. All 20 patients with positive radionuclide angiographic and scintigraphic results had transmural acute cholecystitis. None of the nine patients with acute cholecystitis and false-negative angiograms had abscess or gangrene of the gallbladder. Use of radionuclide angiography may enable the prediction of the severity of acute cholecystitis, as nine of 25 patients with positive findings had either gangrenous cholecystitis or pericholecystic abscess. Positive findings on radionuclide angiograms may preclude the need to obtain delayed (beyond 1 hour) cholescintiscans.