Which of the following screening tests is frequently used to confirm acute cholecystitis?

Acute cholecystitis is commonly diagnosed using a HIDA (hepatobiliary iminodiacetic acid) scan, which assesses the function of the gallbladder. In cases of acute cholecystitis, the gallbladder typically does not take up the radioactive tracer injected during the scan due to inflammation and the blockage of the cystic duct by a gallstone. This absence of gallbladder visualization on the HIDA scan is an important finding that confirms the diagnosis.

While other imaging modalities like CT scans can be useful for identifying complications associated with cholecystitis, such as abscesses or biliary obstruction, and can sometimes show thickening of the gallbladder wall or signs of inflammation, the HIDA scan is more specific for demonstrating gallbladder non-visualization, making it a preferred test in certain clinical settings. Endoscopic ultrasound is more often utilized for visualizing biliary stones and evaluating the bile ducts rather than confirming cholecystitis specifically. MRI is not typically used as a first-line diagnostic tool for acute cholecystitis due to its cost and time-intensive nature.