Ultrasonography, HIDA scintigraphy or both in the diagnosis of acute cholecystitis?

The benefit of early surgery for patients with acute cholecystitis is now accepted but rapid accurate pre-operative diagnosis is important and the single best investigation has not yet been clearly established. All 47 patients with suspected acute cholecystitis admitted to a district general hospital during a 6 month period underwent ultrasonic examination and scintigraphy with HIDA within 48 h of admission. In 23 patients acute cholecystitis was proven. Ultrasound correctly diagnosed this in 21 patients but in 2, changes attributed to chronic cholecystitis only were detected. Two false positive ultrasound results also occurred, one in a patient with adenomyomatosis and acute pancreatitis, the other in a case of duodenitis. HIDA scan was diagnostic in 19 patients but in the remaining 4 the presence of abnormal liver function tests accounted for non-visualization of the biliary tree (a non-diagnostic result). In the absence of jaundice a HIDA scan is the more specific test for confirming acute cholecystitis.