Preoperative imaging of left portal vein at the Rex recess for Rex shunt formation using wedged hepatic vein carbon dioxide portography

BackgroundIn children with extrahepatic portal vein obstruction (EHPVO), formation of a mesentericoportal bypass (Rex shunt) restores hepatopetal flow, relieves portal hypertension, and reduces variceal bleeding and hypersplenism. The Rex shunt is created by inserting a vein graft between the superior mesenteric vein and the umbilical segment (Rex) of the left portal vein within the Rex recess of the liver. The preoperative evaluation of a patient with EHPVO includes an accurate assessment of the venous inflow and outflow. The inflow portal vein is readily assessed by ultrasound and magnetic resonance imaging. The outflow intrahepatic portal vein is harder to assess. We report our experience of patients evaluated with wedged hepatic vein carbon dioxide portography (WHVCP).MethodAll children referred for venography from October 2001 to October 2007 were prospectively identified, and clinical and radiologic data were reviewed retrospectively. The imaging findings were correlated to findings at surgery.ResultsEleven children (range, 3-14 years, median, 6 years) were referred for preoperative wedged hepatic venography. The left portal vein at the Rex recess was clearly identified in 9 patients (82%). In the other 2 patients (18%), the Rex segment was not identified despite opacification of left and right intrahepatic portal veins; this was taken to indicate an occluded segment. Wedged venography was performed with carbon dioxide in 10 patients (91%). Carbon dioxide was contraindicated in the final patient because of the presence of a ventricular septal defect.ConclusionOur series demonstrates the use of WHVCP as a diagnostic tool in preoperative assessment of the Rex segment of left portal vein in children with extrahepatic portal vein obstruction.