Final answer:
A gallbladder scan or cholangiography is a diagnostic test that involves injecting contrast material through the liver and taking X-rays to visualize the bile vessels. It helps detect conditions like gallstones or blockages in the bile ducts.
Step-by-step explanation:
The procedure described in the question is called a gallbladder scan or cholangiography. It is a diagnostic test used to evaluate the function and blockages in the bile vessels. Contrast material is injected through the liver, and X-rays are taken to visualize the bile vessels. This helps in detecting conditions like gallstones or blockages in the bile ducts.