MSCTA And 3D-DCE-MRA In The Evaluation Of Receptor's Vessels Before Orthotopic Liver Transplantation And Compare With Pathologic Results

ObjectiveOrthotopic liver Transplantation ( OLT) has become the treatment of choice for patients with end - stage liver diseases. CT and MRI have play an important role in the evaluation of liver transplantation candidate before OLT. The purpose of this study is to determine whether MSCTA and 3D - DCE - MRA will be able to perform a complete and accurate preoperative evaluation of receptors vessel state.Methods1. PatientsBetween May 2002 and Feb. 2005, thirty - four patients underwent MSCTA and 3D - DCE - MRA examinations before OLT operation. (1) MSCTA group (16 cases) : include 5 cases of primary hepatocellular carcinoma, 8 cases of chronic hepatitis B with cirrhosis, 1 case of cholangiocellular carcinoma, 1 case of primary biliary cirrhosis and 1 case of alcoholic liver cirrhosis. (2) 3D - DCE - MRA group (18 cases) : include 4 cases of primary hepatocellular carcinoma, 11 cases of chronic hepatitis B with cirrhosis, two cases of cirrhosis with non - B hepatitis and one case of liver re - transplantation.2. Examination methods(1) MSCTA examination: All scans were performed on a Siemens Somatom Plus 4 Volume Zoom scanner with scan parameters; 120kv, 140mA, 0.5s/rota-tion. All data information was sent to a free standing workstation for volume ren-dering. Ultravist (300 mgl/ml) (1.5 -2ml/kg) was injected as a bolus at 3ml -5ml/s. Arterial phase images were obtained at 22 -25s and portal venous phase images obtained at 60s following initiation of intravenous contrast agent administration.(2) 3D - DCE - MRA examination; All scans were performed on a GE 1. 5T MRI scanner. Contrast enhanced imaging obtained with Gd - DTPA (0.3ml/ kg) administrated at 2.5ml/s, using Smartprep Angiography contrast tracking technique with 3D - TOF - FSPGR fat saturation sequence (TR/TE/TI =5.4/ 1.9/18msec). Arterial phase images, portal venous phase images and balance phase images were obtained. Data information was sent to a free - standing workstation, in which, three dimensional maximum intensity projection (3D -MIP) was used for arterial phase images and multi - planar reconstruction (MPR) for portal venous phase images.(3) Correlation between surgical pathologic histology and radiological imaging: Combined surgical notes with the removal livers of OLT, radiological changes were correlated, including stenosis extent of celiac axis and hepatic arterial vessels, thrombosis of liver venous system ( superior mesenteric vein, portal vein, hepatic vein, inferior vena cava) , collateral vasculature (caused by portal hypertension) and splenic artery aneurysms. Pathological studies were as follows: 1) Measurements of arterial diameter for the major vessels that supply the liver. 2) Diameter of common hepatic artery ( D <3mm) defined as small -caliber hepatic arterial vessel. 3 ) vessel stenosis were divided into mild narro-wing(D <50% ) , moderate narrowing (75% ^ D ^50% ) , severe narrowing ( D ^15% ) and occlusion.(4) Statistical analyses were calculated by using X2 test (SPSS 9.0).Results1. MSCTA evaluation results of receptors vessels before OLT: (1) MSCTA showing of hepatic artery system: The satisfaction rate of showing hepatic arterial vessels was 81.3%. S/N ratio of measuring celiac axis was 18.36 ±4.91. The mean diameter of celiac axis was 3.3 ±0.2mm, and theaccurate rate of measuring hepatic artery by MSCTA was 100% which was verified by surgical pathological histology. Anatomy of hepatic artery can well be delineated by MSCTA. In this 16 cases,Michels type I were in 14 cases,and Michels type III and type IX in 1 case respectively. Surgical pathologic histology verified small - caliber hepatic arterial vessel one case, moderate hepatic artery stenosis one case, and hepatic arteriosclerosis with mild hepatic artery stenosis two cases ( but were negative on CT axial imaging and MSGTA). The false negative rate of MSCTA for arterial stenosis was 50% , and the accurate rate was 50%.(2) MSCTA showing of hepatic venous system; The satisfaction rate of showing hepatic vein, portal vein and inferior vena cava was 62.5% (10/16). S/N ratio of measuring portal vein was 8.52 ±4.23, and the mean diameter of its main branch was 12.4 ±2.7mm. It was verified by surgical pathological histology that accurate rate of measuring portal vein was 100%. Two points of hepatic venous stenosis and inferior vena cava, four cases of collateral vasculature caused by portal hypertension, two cases of portal vein thrombosis (one case was long segment) and one case of inferior vena cava thrombosis were showed in MSCTA, which were verified by surgical pathological histology. One case of hepatic vein thrombosis was found and verified by surgeon , but was negative on CT axial imaging and MSCTA. The false negative rate was 12.5% , and the accurate rate was 87- 5%.2.3D - DCE - MRA evaluation results of receptor's vessels before OLT;The satisfaction rate of showing hepatic artery in 3D - DCE - MRA was 94. 4% (17/18). S/N ratio of measuring celiac axis was 20.58 ±3.74. It was verified by surgical pathological histology that accurate rate of measuring hepatic artery was 100%. Anatomy of hepatic artery can well be delineated in 3D - DCE -MRA, including Michels type I in 13 cases,Michels type II in one case, Michels type III in two cases, Michels type V in one case and Michels type VI in one case. Two cases of small - caliber hepatic arterial vessel, one case of moderate and two cases of severe hepatic artery stenosis were verified by surgical pathological histology. One case of mild hepatic artery stenosis showed in 3D -DCE - MRA was not verified by pathology, the false positive rate was 16.67% ,and the accurate rate was 83. 33%. The satisfaction rate of showing hepatic vein, portal vein and inferior vena cava was 88. 9% (16/18). S/N ratio of measuring portal vein was 13. 43 ±4. 12, and the diameter of main branch of portal vein was 13.1 ±3.2mm. It is verified by surgical pathological histology that accurate rate of measuring main portal vein was 100%. Three points of hepatic venous stenosis and inferior vena cava, six cases of collateral vasculature caused by portal hypertension, one case of portal vein thrombosis and one case of hepatic vein thrombosis showing in 3D - DCE - MRA were verified by surgical pathological histology, and the accurate rate was 100%.3. Results compared between MSCTA and 3D - DCE - MRA:( 1) success rate and complication; All 34 cases of MSCTA and 3D - DCE- MRA examinations were successfully completed. One case (6.25% ) with severe liver cirrhosis underwent MSCTA resulted coma after 2 hours of contrast enhanced examination.(2) Quality of imaging: Both MSCTA and 3D - DCE - MRA were surgical verified correctly for showing anatomy of hepatic artery. The satisfaction rate of MSCTA and 3D - DCE - MRA were 81.3% and 94.4% respectively, and S/N ratio of measuring celiac axis were 18. 36 ±4. 91 and 20. 58 ± 3. 74 ( p > 0. 05). The satisfaction rate of MSCTA and 3D - DCE - MRA were 62. 5% and 88.9% respectively for showing portal vein, hepatic vein and inferior vena cava, and S/N ratio of measuring portal vein were 8.52 ±4.23 and 13.43 ±4.12 respectively which was statistically significant (p <0.01).( 3 ) Vessel disease showing: The accurate rate showing stenosis of hepatic arteries by MSCTA and 3D - DCE - MRA were 50% and 83. 3% respectively, and the false negative rate of MSCTA was 50% , and the false positive rate of 3D- DCE - MRA was 16.67%. The accurate rate of showing thrombosis for portal vein, hepatic vein and inferior vena cava by MSCTA and 3D - DCE - MRA were 87.5% and 100% respectively. The false negative rate for showing thrombosis of venous system by MSCTA was 12.5%.Conclusions1. Both MSCTA and 3D - DCE - MRA can well demonstrate anatomy of hepatic artery and venous system, and can show classification of anatomy of hepatic artery accurately. 3D - DCE - MRA is superior to MSCTA in demonstrating hepatic venous system.2. Both MSCTA and 3D - DCE - MRA have errors in demonstrating stenosis of hepatic artery, but can well demonstrate venues stenosis and collateral venous pathways and venous thrombosis.3. Both MSCTA and 3D - DCE - MRA can provide a comprehensive preop-erative evaluation for vessels of OLT& receptor, and the 3D - DCE - MRA may be the first choice.