American Board of Internal Medicine (ABIM) Certification Practice Exam

What is the purpose of hepatobiliary scintigraphy in the diagnosis of acute cholecystitis?

1. Evaluate gallbladder function

2. Confirm or exclude the diagnosis

3. Assess hepatic blood flow

4. Determine bile duct obstruction

The correct answer is: Confirm or exclude the diagnosis

Hepatobiliary scintigraphy, also known as HIDA scan, plays a crucial role in the diagnosis of acute cholecystitis by confirming or excluding the diagnosis. In the context of acute cholecystitis, this imaging technique is especially valuable because it can visualize the gallbladder and assess its functionality in real-time. During the procedure, a radioactive tracer is injected into the bloodstream, which is taken up by the liver and passed into the bile. If the gallbladder is inflamed or obstructed due to the presence of gallstones, it will not take up the tracer, leading to a "non-visualization" of the gallbladder on the scintigraphy images. This specific finding directly supports the diagnosis of acute cholecystitis. While evaluating gallbladder function and assessing the anatomy of the biliary system are important aspects of hepatobiliary imaging, they are not the primary focus in the context of acute cholecystitis diagnosis. Similarly, while detecting bile duct obstruction can be of relevance in a broader gastrointestinal assessment, it is not the primary aim of this particular imaging when suspecting acute cholecystitis. The main takeaway is that hepatobiliary scintigraphy effectively provides a