The Clinical Study On Hepatic Vessels With 64-slice Spiral Computed Tomography Angiography

Backgrounds and Objective Multi-slice spiral CT angiography (MSCTA) is a noninvasive technique developed in recent years, which is an integration of CT volume acqusition and three-dimensional reformation. Now it is widely used for whole body examination because of its rapid, convenient and high quality features. In liver, MSCTA is mainly used to demonstrate hepatic artery, portal vein and hepatic vein. Traditional digital subtraction angiography (DSA) used to be the gold standard to display and evaluate vessel changes, but it can display only vascular diseases but not liver parenchyma simultaneously, Furthermore, DSA is an invasive technique. With the development of spiral CT, computed tomography angiography (CTA) has become the hot spot in imaging research recently due to its rapid, convenient and non-invasive character. A good many studies have been reported about liver MSCTA, however, few study referring to 64-slice spiral CTA in hepatic vessels. The purposes of the present study were as follows:1) To evaluate the capability of 64-slice spiral CT in displaying hepatic vessels , its clinical value and compare the difference between different postprocessing technique in liver multi-phase angiography; 2) To probe the variants of hepatic vessels and its clinical significance;3)To evaluate the clinical value of 64-slice spiral CTA in the diagnosis of liver neoplasms by a comparasion with DSA .Materials and Methods 209 patients who underwent multiphase enhanced liver scan involved in this study. Initial raw data from all cases were acquired under thin slice and sent to ADW. Maximum intensity projection( MIP), volume rendering(VR) and multiple planar reformation (MPR) were used to reconstruct liver vessel three-dimensionally in arterial phase and portal-vein phase. The demonstration of hepatic artery, portal vein, hepatic vein and vascular changes in hepatic tumor were analyzed and compared with each other.Thirty cases were performed hepatic arterial DSA at the same time and used as reference.Results In the aterial phase, celiac trunk and its branches as well as variants can be demonstrated clearly, the variant rate in this group was up to 32%.No significant difference was found between VR and MIP in displaying hepatic artery branches under grade 2 and tumor feeding artery, however, MIP is better than VR in demonstrating hepatic artery branches smaller than grade 3 and tumor vascular changes with great significance (P<0.05). Of the 30 patients with hepatic tumor underwent DSA examination at the same time, MSCTA had the same ability as DSA in displaying feeding artery and no significant difference was found in displaying hepatic artery under grade 3, but DSA is better than MSCTA in displaying hepatic artery smaller than grade 4 with great significance (P<0.05). Portal vein and hepatic vein grade 5 to 6 normal branches could be demonstrated on 64-slice CTA and no significant difference was found between VR and MIP. Grade 1 branches of portal vein had five sorts of variant in the 97 enrolled cases, variant rate was 27.8%.There are two types of hepatic vein in 84 cases enrolled in this study, among which type I accounted for 95% (80 cases) and type II 5% (4 cases),and right posterior segment of hepatic vein can be displayed in 7 cases, exhibition rate were 8.3%.The Incidence of hepatic arterioportal fistula in hepatic tumor in the present group was 16.3%, neoplastic embolus in portal vein was 30.6%, In 35 cases hepatic cirrhosis(patients with hepatocellular carcinoma,HCC were excluded), main portal vein thickened and branches reduced were found in 29 cases, varicose of left gastric vein, oesophageal veins and fundus gastricus vein in 19 cases, and 2 cases with cavernous degeneration of portal vein. Feeding artery could be demonstrated in 4 cases of 8 with hepatic angioma and 1 case with focal nodular hyperplasia.Conclusions 1.Compared with traditional spiral CTA, 64-slice spiral CTA can display hepatic artery, portal vein, hepatic venous system, and vascular changes more accurately and especially in the demonstration of tiny hepatic vessel.This technique can meet clinical needs completely and provide accurate information before surgery and intervention.2. A combination of different postprocessing techniques such as VR, MIP and MPR could replace DSA and become the first choice in diagnosing hepatic vascular changes.3. There is fairly high variant rate so far as hepatic artery concerned.It is necessary for us to know the related variants with the aid of MSCTA before surgery .