A cholangiogram is a medical imaging test used to visualize the bile ducts, which are tubes that carry bile from the liver to the gallbladder and small intestine. This procedure helps doctors diagnose conditions such as blockages, infections, or tumors in the bile ducts. It can be performed using X-rays after injecting a contrast dye into the bile ducts. There are two main types of cholangiograms: percutaneous cholangiogram and endoscopic retrograde cholangiopancreatography (ERCP). The first involves inserting a needle through the skin to access the bile ducts, while the second uses an endoscope to inject the dye. Both methods provide valuable information for treatment planning.