What diagnostic method confirms acute cholecystitis in a patient with fever and abdominal pain?

The right upper quadrant abdominal ultrasound is the diagnostic method that confirms acute cholecystitis in a patient presenting with fever and abdominal pain. This imaging technique is particularly effective because it allows for direct visualization of the gallbladder and surrounding structures, enabling healthcare providers to identify signs such as gallstones, gallbladder wall thickening, and pericholecystic fluid. These findings are critical indicators of inflammation associated with acute cholecystitis.

Ultrasound is often the first-line imaging modality used in these cases due to its accessibility, non-invasiveness, and lack of radiation exposure compared to other imaging techniques. It is especially useful in assessing patients with abdominal pain where cholecystitis is a concern.

In contrast, other diagnostic methods listed do not specifically or reliably confirm acute cholecystitis. For example, isolated lymphocytosis may suggest an infection but is not definitive for cholecystitis. Elevated amylase and lipase levels are more indicative of pancreatitis rather than cholecystitis specifically. Abdominal plain films may reveal some indirect signs but are limited in their ability to visualize the gallbladder effectively compared to ultrasound. Thus, the ultrasound stands out as the most appropriate choice for