<prompt> An ultrasound examination shows dilated intrahepatic biliary channels with a small gallbladder. The most likely possibility isGallbladder stonesPancreatic calculusCommon bile duct stoneCarcinoma of the head of the pancreas  <response>: DIAGNOSIS OF CBD STONE USG : first test, can document GB stones and estimate the CBD diameter A dilated bile duct 8mm in diameter in a patient with gallstones, jaundice and biliary pain is highly suggestive of choledocholithiasis MRCP : Provides excellent anatomic detail, with sensitivity and specificity of 95 and 98 respectively, and CBD stones ERCP :Diagnostic and therapeutic test of choice for patients with suspected CBD stones Ref: Sabiston 20th edition Pgno :1494 