Radionuclide biliary scanning with 99 TcVabelled HIDA was performed in 36 patients with acute pancreatitis within 3 days of admission. Twenty had a non-visualized gallbladder on scanning and all were subsequently shown by cholecystography (n = 16) and/or operation (n = 16) to have underlying gallstones; 5 of the 16 cholecystograms revealed a Ifunctioning ' gallbladder. Sixteen patients had normal HIDA scans with gallbladder visualization, and subsequently all were shown by cholecystography (n = IS) or operation (n = I ) to have a