| Part I Studies of anatomy of liver vascular with 64-MSCT three-dimensional reconstructionObjectiveTo analyze the inner anatomical structure and variation of hepatic artery, vein and portal vein through hepatic angiography using three-dimensional reconstruction technique. To investigate the instructive significance for segmentation, liver tumor resection, liver transplantation and intervention for different vascular anatomical structure and variation.Materials and MethodsTotal 60 patients, who were performed upper abdominal examination using triple-phase contrast-enhancement 64-MSCT in the first affiliated hospital of Soochow university, were collected into this study in a period of 6 months, from Jan to Jun, 2008. All of the data sets were transfered to workstation after being reconstructed in 1-mm section and 1-mm interval. Two radiologists took the charge of dealing with the data sets for maximum intensity projection (MIP), volume rendering (VR), surface shadow display (SSD), multi-projection intensity rendering (MPVR) and angiography. Furthermore, analyzed by 1 radiologist and 1 surgeon majoring in liver surgery, the anatomical structure of hepatic artery, vein and portal vein were classified according to certain standards and the rates of variation were recorded. Results1. Among the 60 patients, there were 47 patients (78.3%) belonging to Michels type I (normal hepatic artery anatomy), and other 13 patients (21.7%) showing the existence of variation. They were typeⅡin 1 (1.7%), typeⅢin 4 (6.7%), typeⅤin 2 (3.3%), typeⅥin 3 (5.0%), both typeⅧand typeⅨin 1 (1.7%), and there was no typeⅩ,Ⅳ, andⅦ. However, a special variation type without proper hepatic artery was presented, which could not be included in the Michels Classification.2. Normal portal vein anatomy (type I) was shown in 49 cases (81.7%), typeⅡin 7 (11.7%), typeⅢin 3 (5.0%) and typeⅣin 1 (1,7%). There was no special variation founded.3. Most cases (52/60, 86.7%) of RHV drained into IVC alone (belonging to type I) , and MHC combined with LHV into IVC. Less cases (8/60, 1.33%) of these three hepatic vein drained into IVC respectively (typeⅡ). There were 14 cases (23.3%) showing the existence of inferior right hepatic vein (IRHV). Following to Nakamura Classification, 46 cases (76.7%) were presented in normal type (type I), typeⅡin 10 (16.7%), and typeⅢin 4 (6.7%).Conclusion1. The application of triple-phase scanning with 64-MSCT make it possible to acquire hepatic angiography with a higher resolution, depending on some functional software, such as MIP or VR. Compared with the conventional examination DSA, 64-MSCT three-dimensional reconstruction is a non-invasive and convenient vascular examination, which can provide complete and comprehensive information to observe the inner structure of vascular and the lesion from different angles.2. 64-MSCT three-dimensional reconstruction can make it more clearly to understand the anatomical structure and the variation of inner hepatic vascular system. It has significantly valuation in segmentation, planning for tumor resection, intervention treatment of liver malignance and liver transplantation, especially in living-donor liver transplantation. Key Words: multi-slice computed tomography, liver, three-dimensional reconstruction, angiography, variationPartⅡClinical application of liver volumetry in hepatic surgeryObjectiveTo evaluate the accuracy and reliability of liver volumetry using different methods and also to investigate the clinical value of liver volumetry in assessing liver functional reserve and as a parameter to predict the prognosis after major hepatectomy.Materials and MethodsThere were 50 patients, who were performed major hepatectomy, and 6 patients, who were performed orthotopic liver transplantation, in the first affiliated hospital of Soochow university from January 2008 to December 2009, were collected into this study and analyzed retrospectively. All of the patients were examined by triple-phase contrast-enhancement 64-MSCT and were applied for three-dimensional reconstruction. Three different kinds of workstation software were used to measure the volume of liver, such as Leonardo (Seimens Medical Solution), bundled with 64-MSCT, eFilm Workstation TM 2.1 (Merge Healthcare) and Myrian○R XP-Liver (Intrasense○R , France). Total liver volume (TLV), tumor volume (TuV) were measured by 64-MSCT. Functional liver volume (FLV), virtual resected liver volume (vRLV), remnant liver volume (RLV) and relative residual liver volume (%RLV) were calculated. All the results were compared with the actual volume, which was measured by the method of water displacement after tumor resectionAll the pre-, peri- and post-operative information were recorded, such as sex, age, weight, height, C-P classification, operating time, blood loss and the remnant liver volume, complications and so on. Univariate analysis and multivariate logistic regression analysis were performed to delineate perioperative predictors of severe hepatic dysfunction. Receiver operator characteristic curve analysis was undertaken to determine the critical %RLV predicting severe hepatic dysfunction. Results1. The mean TLV of 56 patients measured by three different methods was 1355.9±806.8cm3, 1438.9±344.7cm3 and 1450.4±354.2 cm3. The mean volume of virtual reseced specimen volume (vRSV) was 754.9±326.8cm3, 740.7±322.1cm3 and 753.6±330.1 cm3. Compared with the mean volume of actual resected specimen volume (aRSV) using water displacement was 729.3±332.4 cm3 and the mean weight was 718.30±327.15g. Comparison by means of linear regression analysis between volume measurement on the software and the actual resected volume and weight showed a nearly ideal correlation coefficient (r=0.948, 0.927and 0.945, P<0.05; r=0.995, 0.986 and 0.980, P<0.05).2. Univariate analysis revealed that intraoperative blood loss, RLV and %RLV were significant prognostic indication for severe hepatic dysfunction. The incidence of severe hepatic dysfunction following hepatic resection increased significantly with smaller %RLV. A critical %RLV of 0.32 was identified as associated with severe hepatic dysfunction (P<0.05).Conclusion1. Three methods used for measuring the volume of liver have different characteristics. Myrian○R XP-Liver was recommended for its convenience and efficiency.2. Although the results measured by these three methods were different with actual volume measured by water displacement, all of them had a proper linear correlation with actual results.3. Residual liver volume after virtual hepatectomy could be a predictor of hepatic dysfunction. The likelihood of severe hepatic dysfunction following hepatic resection can be predicted by a small %RLV. Reducing the intraoperative blood loss and increasing the RLV as much as possible can decrease the risk of hepatic post-operative dysfunction. PartⅢImpact of virtual hepatectomy and computed-assisted risk analysis on operation planning and intraoperative strategy in major hepatic resectionObjectiveTo evaluate the impact of virtual hepatectomy and computed-assisted risk analysis on operation planning for major hepatectomies, in particular on extent of resection or need for vascular reconstruction.Materials and MehtodsTwenty-two consecutive patients (17 male, 5 female; median age, 47 years) admitted to the first affiliated hospital of Soochow university from January to December 2009 for complicated major hepatectomy. Underlying tumors were primary hepatocellular carcinoma (n=14, 63.6%), metastases of colorectal cancer (n=2, 9.1%), hemangioma (n=3,13.6%), Klaskin's tumor (n=2, 9.1%) and gallbladder carcinoma (n=1, 4.5%). The CT scanning was performed with 64-MSCT (Somatom Sensation 64, Germany). All the data of imaging was imported into Myrian○R XP-Liver (Intrasense○R , France) system, and the three-dimensional reconstruction model was performed for virtual hepatectomy. The following steps were taken by 1 radiologist and 1 surgeon majoring in liver surgery: step 1, image analysis and 3-D reconstruction; step 2, virtual resection and liver volumetry; step 3, computer-assisted risk analysis for the hepatic dysfunction, and adjustment of the operation planning.Results1. The three-dimensional reconstruction model of liver by Myrian○R XP-Liver system is visualized and verisimilar. The ideal simulation effect can be achieved compared the virtual image with actual operation.2. Overall, 22 patients underwent complicated major hepatectomy and in 20 of the 22 resections, complete tumor removal was achieved (R0 resection). The achieved safety margins ranged from 4mm to 4cm, with a median of 1.8 cm. There was 2 cases R1 resection. In these 2 cases, there were microscopic tumor at the cutting margin of the right portal vein and bile duct. There was no one died in operation and hospital stay. 2 cases appeared severe hepatic dysfunction after operation and was discharged 2~3 weeks later after conservative treatment. One of them died of severe upper gastrointestinal bleeding three months later.3. In 6 patients, the results of computer-assisted risk analysis made us change operation planning and surgical strategy with regard to extent resection or the need for vascular reconstruction. With the planning, an optimal identification of safety resection margins could be achieved. The volume of remnant liver and the ischemia/congestion territory within the remaining parenchyma can be calculated. The operation planning and intraoperative strategy were adjusted to avoid liver parenchyma over resection and maintain a sufficient amount of liver tissue to sustain hepatic function.ConclusionThe application of hepatic three-dimensional reconstruction and virtual hepatectomy, using Myrian○R XP-Liver system, can provide the important preoperative reference for a valuable planning and intraoperative strategy of complex hepatectomy. |
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