Bile is a thick fluid secreted by the liver and stored in the gallbladder. It is then released into the upper intestine to help digest food and break down fats. Bile travels from the liver to the gallbladder and the intestine through canals called ducts. Diseases such as stones and cancer can clog the ducts. Doctors can use several tests to diagnose clogged or obstructed biliary tract ducts. Many are “invasive” tests: They require putting a tube down the patient's mouth, injecting dye through a vein, or inserting a needle into the liver. A relatively new noninvasive test is magnetic resonance cholangiopancreatography (MRCP). This test takes detailed pictures of bile and the biliary tract. Many studies have examined the accuracy of MRCP for diagnosing biliary disease compared with other tests. Do these studies show that MRCP is an accurate test in certain situations and not in others?