<prompt> Linear filling defect on ERCP is characteristic of which of the following :Bile duct stonePancreatic duct stoneWorm in biliary treeStricture  <response>: Linear filling defect in main CBD is a characteristic feature of BILIARY ASCARIASIS. ERCP is the gold standard but an invasive method. It is used also in the extraction of CBD worms. The worms appear as a hypointense structure within the hyperintense CBD giving linear filling defect on MRCPERCP 