<prompt> Initial investigation of choice in obstructive jaundice isUSGERCPCT scanPTC  <response>: Transabdominal ultrasound scan is universally established as the most useful first line imaging study in the jaundiced adult.It provides an excellent evaluation of liver parenchyma assessment of the presenceabsence of bile duct dilatation. Reference:SRBs manual of surgery,5th edition,page no:656. 