Needle orientation for transhepatic cholangiography: CT localization of the porta hepatis.

The needle orientation recommended for transhepatic cholangiography has a consensus in the literature for the sagittal and the transverse planes. Because of differing recommendations for the needle orientation in the coronal plane, the location of the porta hepatis was analyzed in 50 patients undergoing computed tomography. The mean ratio between skin to the porta hepatis distance and AP patient diameter is 0.38. The best puncture site therefore lies anteriorly to the halfway mark at the midaxillary line by about 3 cm.