Cholescintigraphy is slightly more accurate, but ultrasound is more readily available.
Ultrasound (US) and cholescintigraphy (e.g., hepatobiliary iminodiacetic acid [HIDA] scanning) are used widely to evaluate patients with suspected acute cholecystitis. Additionally, emergency department clinicians sometimes order computed tomography (CT) as the initial test, especially when they are considering both biliary and nonbiliary causes of abdominal pain.
To address the diagnostic accuracy of imaging tests for acute cholecystitis, researchers performed a meta-analysis of 57 studies with explicitly stated criteria for positive tests and with surgery and clinical follow-up as reference standards. Cholescintigraphy was evaluated in 40 studies, and US was evaluated in 26 studies; CT and magnetic resonance imaging were evaluated in only 1 and 3 studies, respectively. For cholescintigraphy, sensitivity was 96% and specificity was 90%; nonvisualization of the gallbladder was the usual criterion for a positive test. For US, sensitivity was 81% and specificity was 83%; criteria for a positive test varied widely, from simple presence of gallstones to combinations of additional findings (e.g., wall thickening, distention, pericholecystic fluid, sonographic Murphy sign).
Comment: Although US might be less accurate than cholescintigraphy, it remains a reasonable initial procedure, because it is simple and inexpensive to perform. The investigators’ figures for sensitivity and specificity of US should be considered only approximations, given the varying criteria for positive tests across studies. Cholescintigraphy should be done when US results are ambiguous. Despite widespread use of CT for initial evaluation of abdominal pain, its accuracy for acute cholecystitis has not been studied adequately.
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ARYAN'S BLOG 