DUAL-PHASE SPIRAL CT ANGIOGRAPHY WITH VOLUMETRIC 3D RENDERING FOR PREOPERATIVE LIVER-TRANSPLANT EVALUATION - PRELIMINARY-OBSERVATIONS

Purpose: The goal of our study was to determine whether dual-phase spi ral CT angiography with 3D volume rendering could be used for preopera tive evaluation and patient selection for orthotopic liver transplanta tion candidates. Method: Fifty consecutive potential candidates for li ver transplantation were evaluated with dual-phase spiral CT with 3D v olume rendering. Intravenous contrast medium was administered as bolus peripheral injection at 3 ml/s. The protocol consisted of a contrast- enhanced dual-phase spiral CT (arterial phase acquisition at 30 s afte r initiation of contrast medium injection followed by portal venous ph ase beginning at 60 s) with scan parameters of 0.75 s gantry rotation speed, 3 mm collimation, 5 to 6 mm/s table speed, and reconstruction a t 1 mm intervals for arterial-phase images and 3 mm collimation for po rtal venous-phase studies (Siemens Plus 4 scanner; Siemens Medical Sys tems, Iselin, NJ, U.S.A.). All scan information was sent to a free-sta nding workstation (Silicon Graphics Onyx or Infinite Reality, Mountain View, CA, U.S.A.) for interactive real-time 3D volume rendering using a customized version of the Volren volume renderer (Silicon Graphics; Advanced Imaging Laboratory, Johns Hopkins Medical Institutions, Balt imore, MD, U.S.A.). The arterial phase was used to create vascular map s of the celiac axis including the origin(s) of the hepatic artery and origin of the superior mesenteric artery. The portal phase was used t o define portal venous patency as well as the hepatic venous anatomy. All images were analyzed for vascular patency, shunting, or collateral ization as well as the status of the underlying liver (i.e., liver siz e, cirrhosis, tumor, etc.). Results: All 50 studies were successfully completed without complication. The 3D CT angiograms defined key arter ial and venous structures including origin(s) of the hepatic artery, p ortal vein and/or superior mesenteric vein thrombosis, cavernous trans formation of the portal vein, and/or other collateral vasculature. Ten patients (20%) demonstrated anomalous anatomy at the origin(s) of the hepatic artery. Portal vein thrombosis with cavernous transformation of the portal vein was shown in six patients, and there were three cas es of partial venous thrombosis. Underlying liver tumors as well as pa renchymal liver disease were well defined. Hepatic masses were found i n five patients. Masses were pathologically proven as hepatocellular c arcinoma(n = 1), giant cavernous hemangioma (n = 1), hepatic adenoma ( n = I), and focal nodular hyperplasia (n = 2).Conclusion: Preliminary results suggest that dual-phase spiral CT with CT angiography can prov ide a comprehensive preoperative liver transplant evaluation, supplyin g the necessary information for patient selection and surgical plannin g. As a single, minimally invasive examination, this should significan tly impact patient care by minimizing procedures and avoiding potentia l complications.