Figure 4a.  Absence of artifacts secondary to a transjugular intrahepatic portosystemic shunt and spinal fixation rods in a 51-year-old man with elevated alkaline phosphatase levels. MR cholangiography was performed to assess for bile duct obstruction. (a) Digital angiogram obtained during placement of a transjugular intrahepatic portosystemic shunt shows the metallic shunt (arrows) and spinal fixation rods (arrowheads). (b, c) Subsequent MR cholangiograms demonstrate the proximal (b) and distal (c) extrahepatic bile duct (arrows) and help exclude biliary obstruction despite the presence of the transjugular intrahepatic portosystemic shunt and the spinal fixation rods. Note the signal void (*) caused by the shunt.