A magnetic resonance cholangiogram (MRC) is a test that can help doctors look for problems in the belly. The image is done from outside the body. No instruments are inserted in the body.
Doctors can use MRC to find gallstones before surgery to remove the gallbladder (laparoscopic cholecystectomy). But the test is most useful for diagnosing complications of gallstones. These include obstruction of the bile duct, perforation of the gallbladder, and abscesses.
The disadvantage of MRC is that doctors can't use it to remove gallstones. With ERCP (endoscopic retrograde cholangiopancreatogram), they can.