Common Bile duct is part of the “plumbing” that drains the secretion of the liver (bile) into small bowel (duodenum).  The size of the common bile duct, if dilated, may suggest a blockage downstream. This is a specific finding that is looked for when a patient gets an ultrasound for a suspected liver or Gallbladder disease. When a patient has their gallbladder removed, the common bile duct dilates over some time. Dilated common bile after a cholecystectomy is of no significance by itself and should only be considered important if there are other findings, such as pancreatitis or elevated liver function tests.It is, however, important to remember that for any patient who has had the Duodenal switch operation, or the Gastric bypass procedure, the altered anatomy precludes the option of MRCP as a diagnostic or Therapeutic study.