Zeman R K, Burrell M I, Cahow C E, Caride V
Am J Surg. 1981 Apr;141(4):446-51. doi: 10.1016/0002-9610(81)90138-0.
When faced with a patient with possible acute cholecystitis, technetium-99m-HIDA scintigraphy should be the primary diagnostic procedure performed. If scintigraphy reveals a normal gallbladder, acute cholecystitis is excluded. If the scintigram fails to visualize the gallbladder, ultrasonography is deemed advisable to exclude potential false-positive scintigrams and confirm the presence of cholelithiasis.