Clinical Application Of Three-dimensional Visualization Technology In The Diagnosis And Treatment Of Portal Hypertension

BackgroundCollateral circulation vessels are a consequence of the portal hypertension. Their prognosis is strongly marked by the risk of digestive hemorrhage, especially esophageal and gastric bleeding, and hepatic encephalopathy. Nowadays, the therapeutic management of hepatic portal hypertension is still a challenge, which the treatments and surgical options were incredibly various, and none of them could produce effective long-term efficacy. However, there has been much argument about the choice of surgical procedure in the clinical practice, including making the decisions of grabing the best opportunity for the surgical operation, selecting portalazygous disconnection or porta-caval shunt, choosing Hassab’s procedure(or extended Hassab’s procedure), Sugiura’s procedure(or modified Sugiura’s procedure),or selective pericardial revascularization, deciding which operation type of portacaval shunt to be adopted, deciding to receive splenectomy or preserving spleen, etc. Therefore, completely grabbing the formation of collateral circulation and evaluating hemodynamic changes undoubtedly provided evidences to solving the issues above-mentioned.Multi-slice computed tomography portography(MSCTP) has become one of the most important non-invasive technology to master and assess the portal venous system and portal-systemic collateral circulation. Three dimensional (3D)reconstruction based on lamellar reconstructed came to be true by MSCTP that realized long range of volume scanning during a short period of time and that obtain more high-quality reconstructed image of blood vessel by lamellar reconstructed of different layer and spacing. At present,3D angiography techniques base on CT mainly include volume representation (VR) and maximum density projection (MIP), although VR can produce realistic image with living3D visual effect,3D image of venous are displayed poorly and usually disturbed by surrounding soft tissue, which the CT value is similar to venous system in portal venous phase, therefore the3D reconstruction of the venous system usually using MIP. MIP can locally display the venous system well, however,it unable to show panorama of the portal venous system and collateral circulation which usually obscure each other in space, so we may easily cause erroneous judgment,especially when trying to evaluate some small or roundabout vein such as the posterior and short gastric veins. Collateral circulation in various parts of the patients body with portal hypertension show up as complicated, tortuous and mutually connected,which loses its normal anatomical structure and has individual difference.Thus, it is essential that the3D reconstruction of relevant organs such as stomach or spleen to be performed at the same time,and to observe the spatial relation with target blood vessels by showing under rotating, scaling, combination or transparency according to user’s needs.All kinds of software for3D reconstruction based on CT date was widely used in clinics, such as Myrian XP-liver system (French), EDDAIQQA-Liver system (America), MEVIS system (Germany), Liv1.0(China).3D medical image diagnostic workstations (3D med, Chinese Academy of Sciences, etc. However, the software was mainly focused on the pre-operative planning of hepatectomy. In the present study, we used a medical image processing system named Medical Image Three-Dimensional Visualization System (MI-3DVS, software copyright No.2008SR18798) with ourselves-owned intellectual property rights, to perform3D reconstructions.Since2006, MI-3DVS has been proven a useful preoperative approach for diagnosis and surgical planning in hepatolithiasis, liver tumor,and pancreatic tumor. Along with incessant improvement and development of the software, the speed of segmentation and sophistication degree of blood vessels model were enhanced effectively, and the3D models could be processed with smoothing, denoising, and setting colors in the "tools of surface rendering data" module without the help of the Free Form Modeling System.Purpose1. Through vividly show the3D morphology characteristics of collateral circulation in various parts of the body, evaluate image effect of using the system for reconstruction.2. Show the superiority of the software by comparing with MIP and VR.3. According to the distribution and blood supply of EGV, discussed the3D reconstruction of classification of the EGV, and exploring practical value in clinical.4. Explore the superiority of MI-3DVS in the diagnosis of portal hypertension and the guided value for establishing the therapeutic project integrated with surgical operation process.Patients and Methods1. Patients informationThin-section CT scans date of patients with definitive diagnosis of portal hypertension in Zhujiang Hospital (Southern Medical University, Guangzhou, Guangdong, China) during February2010and August2012were recruited into the present study. Inclusion criteria:(1) With clinical diagnosis of portal hypertension, MSCTP showed esophageal gastric varices;(2) With clinical diagnosis of portal hypertension, MSCTP showed obvious collateral circulation without showing esophageal gastric varices;(3) With clinical diagnosis of regional portal hypertension, MSCTP showed esophageal gastric varices,or with a history of esophageal varices hemorrhage. Excluding criteria:(1) With operation history on upper abdominal region, except cholecystectomy and exploratory choledochostomy;(2) Cavernomatous transformation of portal vein caused by portal vein tumor thrombus in patients with hepatocellular carcinoma.(3) With a therapy history of endoscopic injection of tissue adhesive for gastric varices bleeding, percutaneous transhepatic fixed e embolization, or transjugular intrahepatic portosystemic stent shunt.57cases(44males,13females, mean age52.7±12.5, range15-77) met final selection criteria and were analyzed. The ethics committee of the Southern Medical University approved this study. All the patients received upper abdominal64-slice multidetector CT portography (64-MDCTP) scanning which was3D reconstructed for abdominal organs and blood vessels using MI-3DVS. In the evaluation of liver function using the Child-Pugh classification,35patients (61.4%) were in class A,11(19.3%) were in class B, and11(19.3%) were in classC.19patients (33.3%) had upper alimentary canal bleeding,11patients (19.3%) of recurrence of bleeding.52patients (91.2%) had hepatic cirrhosis,31cases (55.4%) with hepatitis B virus surface antigen positive. Clinical symptoms:21cases with different degree of ascites (36.8%);20cases (35.1%) with abdominal veins showing or varicose;54cases (94.7%) of the different degree of splenomegaly,18cases (31.6%) could to touched under the rib,32cases (56.1%), with different degree of the hypersplenism;9cases (15.8%) with liver cancer.4patients were cavernous transformation of portal vein(CTPV),3patients were regional portal hypertension, and3patients were Budd-Chiari Syndrome(BCS). Exclusive criteria:Patients had the history of operation in upper-abdomen.2. Materials(1) PHILIPS BRILLIANCE64-slice helical CT, Image process workstation;(2) binocular tube high pressure injector and contrast agent;(3) computer;(4) Medical Image3D Visualization System (MI-3DVS).3. Imaging scan parametersWhich were described in detail in the text and reference section.4. Data collectingWhich were described in detail in the text and reference section. 5. Methods of3D reconstruction3D reconstruction using VR and MIP were confirmed together by researchers and radiologists in Mxview workstations; and3D reconstruction using MI-3DVS were done by the researchers.The methods of3D reconstruction using MI-3DVS: The CT data of each phase was introduced into MI-3DVS in DICOM format for segmentation and3D reconstruction. We used the CT data of portal venous phase for segmentation and3D reconstruction of blood vessles in the " reconstruction of vascular " module of MI-3DVS, the segmentation of image adopted "threshold segmentation". We used the CT data of portal phase for segmentation and3D reconstruction of relative organ in the " reconstruction of organ " module, the segmentation of image adopted "region growing method". Finally,the optimized segmentation result was reconstructed for3D models which could also Be processed with smoothing, denoising, and setting colors in the "tools of surface rendering data" module.6. Target blood vessels includingLeft gastric veins (LGV), short gastric veins (SGV), posterior gastric veins (PGV), esophageal and gastric varices (EGV), paraesophageal varices (PEV),spontaneous spleno-renal or gastro-renal shunts, umbilical vein, venae parumbilicales, abdominal wall veins, paragallbladder varices, intrahepatic shunt, omentum veins, and retroperitoneal varices.7. Research design(1) MI-3DVS,VR and MIP were all adopted to3D reconstruction for the collateral vessels in spleen and stomach area, and evaluated the displaying rates and the visual quality of the images. The judgement standard for displaying:In the MI-3DVS, VR,2centimeter up of the starting position of the LGV, the SGV and PGV were displayed and extened; the extension and starting position of the PEV and the spontaneous splenorenal or gastro-renal shunts were displayed. In the MIP, the extension and starting position of the varicose vein were displayed.(2) According to the distribution and blood supply of EGV, discussed the3D reconstruction of classification of the EGV.(3) Using MI-3DVS for preoperative planning, and exploring practical value in clinical.8. Statistical treatmentAll statistical analyses were performed with SPSS13.0statistical software. Difference between measurement data (displaying rates of collateral vessels using MI-3DVS,MIP and VR) were compared through analysis of variance and that between groups with Bonferroni test.9. Operative compare13cases were carried on surgery according to3D image data of collateral circulation and portal venous system.The result of operative exploration and data of imageology were carried on to be contrasted, analyzed and summarized to estimate the value of MI-3DVS in the diagnosis and treatment of portal hypertension.ResultsPortal system and collateral circulation were showed systematically and completely even most of small collateral vessels, the3D models were beautiful and strong sense of substantiality; Collateral circulation in various parts of the patient’s body which wershowed more vividly and accurately by combined with relevant organ had different characteristics.1. Comparation of the displaying rates of collateral vessels among the reconstruction using MI-3DVS,MIP and VRThe displaying rates of collateral vessels, including left gastric vein (91.2%VS89.5%VS68.4%,), short gastric vein (68.4%VS73.7%VS.17.5%), posterior gastric vein (43.9%VS49.1%VS.43.9%), paraesophageal varices (49.1%VS52.6%VS.12.3%), gastro-renal shunts (24.6%VS22.8%VS10.5%), etc.show the significant differentiation among MI-3DVS,MIP and VR P<0.05(P=0.000). Difference between between groups were compared through analysis of Bonferroni test, there is no significant difference of MI-3DVS and MIP P>0.05(P=0.933); the displaying rates of MI-3DVS is significantly higher than that of VR P<0.05(P=0.001).2. The3D characteristic of the collateral circulation in various regions of the body using MI-3DVSThrough a typical3D image displaying of collateral circulation to To illustrate the results, including:esophageal gastric spleen and stomach area, pontaneous spleno-renal or gastro-renal shunts, umbilical vein, venae parumbilicales, abdominal wall veins, paragallbladder varices, intrahepatic shunt, omentum veins, and retroperitoneal varices.3. Results of the the3D typeWe divided the51cases with GEV into type A (type A1and A2), B (type B1and B2), and type C according to the distribution and blood supply of EGV, and with the patients of17cases (33.3%),17cases (33.3%),5cases (9.8%),4cases (7.9%),8cases (15.7%) respectively.4. Operative compare13cases were carried on surgery according to3D image data of collateral circulation and portal venous system, including9with portalazygous disconnection,2with proximasplenocaval shunt,1with distal pancreatectomy, and1with splenopneumopexy.Conclusion1. MI-3DVS can show the starting and ending points, distributions, courses, and anastomosis, space position relations of the portal system and collateral circulation completely and systematically.2. MI-3DVS is of superiority in displayed rate of collateral circulation and image effect, comparing with the VR and MIP. 3. MI-3DV could displayed the blood supply relationship of EGV and LGV, SGV, PGV. Combined with the3D reconstruction of the stomach models, the precise location, diameter and shape of EGV could accurately positioned. The3D reconstruction of classification of the EGV were discussed,and with guiding value for preoperative planning.4. MI-3DVS is helpful for us to completely grab the formation of collateral circulation and has guidance and current significance in optimizing therapeutic schedule and preoperative planning.