Which of the following investigations is considered the most sensitive for diagnosing gallstones?

Endoscopic ultrasound (EUS) is regarded as the most sensitive investigation for diagnosing gallstones due to its ability to provide high-resolution images of the biliary and gallbladder structures. EUS has excellent sensitivity and specificity, making it particularly effective in detecting small stones within the gallbladder or biliary tract that other imaging modalities might miss.

The technique involves the insertion of an endoscope with an ultrasound probe into the duodenum, allowing for close proximity to the gallbladder and bile ducts, which enhances the visualization of stones and associated complications. This method is particularly valuable in cases where patients present with symptoms of gallstone disease but have inconclusive results from other imaging studies.

In contrast, while abdominal X-ray can visualize some gallstones, particularly those that are calcified, it does not capture all types of gallstones effectively, making it less sensitive than EUS. Magnetic resonance cholangiopancreatography (MRCP) is also highly useful for visualizing the biliary tree and stones but is generally considered less sensitive than EUS for gallbladder stones specifically. Additionally, a CT scan of the abdomen, while useful in determining the presence of gallstones and complications, may not always identify small stones due to the different