Hepatic Blood Supply: A Study Of Multislice CT Angiography

Object: To explore the feasibility of reconstructing the hepatic vessels by multislice spiral computed tomography (MSCT) during an injection of contrast media, to discuss the accuracy of delineating the hepatic arterial anatomy with MSCT compared with conventional angiography, and to optimize the delay time and postprocessing techniques of the portal vein. Materials and Methods: 84 cases were classified into 4 groups which were performed enhanced scanning at 25s, 50s; 25s, 55s; 25s, 60s; 25s, 50s, 75s after the initiation of injection at the rate of 3ml/s with the volume of contrast media according to 1.5ml/kg body weight after the plain scanning. Raw data of another 16 cases were acquired at 25s after initiation of injection of contrast media. Over the scanning, one radiologist processed all raw data using postprocessing software of maximum intensity projection (MIP), surface shadow display (SSD), and volume rendering (VR). Two radiologists assessed all images in consensus. According to Michels' classification of the hepatic artery, 100 cases of MSCTA of the hepatic artery were classified. 26 cases were performed digital subtraction angiography (DSA) after or before CT angiography (CTA) examination, the interval time was one month or so, two DSA images were precluded because of hyper-selection of the common hepatic artery or the right hepatic artery for assessment of hepatic arterial anatomy and for analyzing the hepatic arterial segment. The assessing contents included visualization of the hepatic artery and the anatomy of hepatic artery and variants. The order of the portal vein and the value of three post-processingtechniques were compared; and CT number of the portal venous trunks and the hepatic parenchyma and their subtraction were analyzed among three groups, meanwhile, the anatomy and variants of the portal vein and the hepatic vein were recorded. Results: CTA showed the tertiary and more order branches of the hepatic artery in all cases; the rate of concordance with DSA was 99.4%; the accuracy of visualizing anatomy of the hepatic artery and variants was 95.8%; The normal type of the hepatic artery accounted for 69%, the aberrant hepatic artery 31%. The image quality of the portal vein in the 50s group was better than that in the 60s group and in the 55s group, having statistical difference; VR and MIP had a similar ability to show the portal vein, and better than SSD. The normal type of the portal vein accounted for 86.9%, and the variants 13.1%. The visualization of the hepatic vein in the 60s group and in the 75s group was higher than that in the 50s group and in the 55s group. The visualization rate of the hepatic vein was 60% and the right posterior vein 34%. Conclusions: Reconstruction of hepatic vessels by MSCT during an injection of contrast media is feasible; CTA has a high accuracy for delineating the hepatic vascular anatomy in comparison with DSA; the delay time of 50s and the post processing techniques of VR and MIP can better display the portal vein.