How is dx of acute cholecystitis?

Leukocytosis (lab) Radio: US most useful, murphy's sign (focal bladder tenderness under sonography 90% acute cholecystitis) US also detects nonspecific findings suggesting it, such as pericholecystic fluid/ wall thickness (>4mm) but they lose their specificity if pt has ascites or hypoalbuminemia (suggesting liver disease) CT: for detection of complications