Final answer:
The abdominal ultrasound is the primary non-invasive diagnostic study for detecting gallbladder cholelithiasis. If more detailed or functional assessment is needed, an endoscopic ultrasound, MRCP, HIDA scan, or ERCP can be employed.
Step-by-step explanation:
When evaluating for biliary tract or gallbladder cholelithiasis, the diagnostic study of choice is typically an abdominal ultrasound. This non-invasive test provides detailed images of the gallbladder and can detect gallstones, inflammation, and other abnormalities. Should further detailed imaging be necessary, endoscopic ultrasound or magnetic resonance cholangiopancreatography (MRCP) may be used. The former involves a probe attached to a scope inserted down the throat to view the organs, while the MRCP uses magnetic waves to produce detailed pictures of the bile ducts and surrounding organs. For dynamic studies of the gallbladder function, HIDA scan or gallbladder scan, involving radioactive tracers, can be informative.
In cases where biliary duct structure needs to be assessed, an endoscopic retrograde cholangiopancreatography (ERCP) might be performed. This invasive procedure inserts a tube via the throat to inject dye into the bile and pancreatic ducts, which is then visible on X-ray.