基于相衬CT的肝纤维化胆管增生三维结构可视化及定量分析研究

发布时间：2018-03-13 03:19

本文选题：相衬CT　切入点：胆管结扎　出处：《天津医科大学》2017年硕士论文　论文类型：学位论文

【摘要】：X射线相位衬度成像(phase-contrast imaging,PCI)简称相衬成像,在揭示生物样品内部细节结构方面已展现出其优势。与传统的基于吸收的X射线成像方法不同,相衬成像的衬度变化来自于相位位移,即当X射线穿过样品时引起的相位移动,相衬成像产生的图像衬度变化大约是吸收衬度变化的1000倍。近年来,相衬成像结合CT成像(相衬CT)发展很快,在具有弱吸收衬度的生物软组织成像中,可用来评估软组织内部微小的密度变化。本研究利用相衬CT成像技术,重建了胆管结扎诱导肝纤维化大鼠肝脏组织中及人胆汁性肝硬化样品组织中的脉管微观结构,并利用定量分析指标评估了肝纤维化发展过程中脉管微观结构的改变,主要研究内容如下:(1)、本文首先探究了相衬CT成像技术在胆管结扎诱导肝纤维化增生胆管三维成像上的可能性。10只Sprague-Dawley大鼠平均分成两组:假手术组和胆管结扎纤维化组。同时,引入人体胆汁性肝硬化样品,利用相衬CT高分辨率三维可视化技术对肝脏样品进行成像。结果表明,在胆管结扎诱导肝纤维化模型中,相衬CT高分辨率三维成像在不注射造影剂的条件下,能够探测到增生胆管的管腔和内壁微观结构。并且由重建的增生胆管三维结构可见增生胆管的分叉,分支的伸长和扭曲,以及管腔表面起褶等特征。通过相衬CT和病理切片的比较,证实相衬CT作为一种无创成像模式在胆管成像上具有高度敏感性。除此之外,通过对人体胆汁性肝硬化样品进行成像,发现增生胆管表面同样存在褶皱现象。研究表明相衬CT可作为一种有效手段评估胆汁性肝硬化疾病中胆管增生的形态学发展变化。(2)、为观察肝纤维化发展过程中增生胆管的变化,在以上实验的基础上,增加了胆管结扎样品分组。除了假手术组和胆管结扎后6周组样品,还包括胆管结扎后2周组、4周组和8周组,每组肝脏样品数量为8个。通过对肝脏样品进行9μm分辨率成像,重建出肝脏脉管树三维结构,并且对其三维脉管密度进行统计。本研究将相衬CT和高分辨率三维可视化技术相结合,重建出肝纤维化发展不同时间点的增生胆管结构。并且基于三维结构定量分析了增生胆管的三维增生密度和分形维数。此外,初步探讨了胆管结扎模型中门脉压力变化机制。研究表明,三维脉管密度随着纤维化时间发展逐渐增大,纤维面积比值逐渐增大,增生胆管数量和动脉数量越来越多。门脉小支缺失、胆管增生、胶原纤维沉积会造成门脉压力值升高,但是在疑似动脉脉管黏连相融、静脉吻合支以及疑似淋巴管膨胀增生等分压作用下,门脉压力值并没有发生明显变化。研究证明相衬CT技术为利用微脉管的改变来评估肝纤维化疾病的发展提供了一种新的方法和方向。
[Abstract]:Phase-contrast imaging (PCI) for short has shown its advantages in revealing the detailed structure of biological samples. Unlike traditional absorption-based X-ray imaging methods, the contrast changes of phase contrast imaging come from phase shift. That is, the phase shift caused by X-ray passing through the sample, the contrast change produced by phase contrast imaging is about 1000 times as much as that of absorption contrast. In recent years, phase contrast imaging combined with CT imaging (phase contrast CT) has developed rapidly. In the biological soft tissue imaging with weak absorption contrast, it can be used to evaluate the tiny density change inside the soft tissue. The vascular microstructures in the liver tissue of rats with hepatic fibrosis induced by bile duct ligation and in the samples of human biliary cirrhosis were reconstructed. The changes of vascular microstructures during the development of hepatic fibrosis were evaluated by quantitative analysis. The main contents of this study are as follows: firstly, the feasibility of contrast CT imaging in three dimensional imaging of hepatic fibrosis induced by bile duct ligation was studied. 10 Sprague-Dawley rats were divided into two groups: sham operation group and bile duct ligation fibrosis group. The liver samples were imaged by phase contrast CT with high resolution 3D visualization. The results showed that in the model of hepatic fibrosis induced by bile duct ligation, liver fibrosis was induced by bile duct ligation. Contrast CT high resolution 3D imaging can detect the microstructures of the lumen and inner wall of the hyperplastic bile duct without injection of contrast medium, and the branching, extension and distortion of the branches can be seen from the reconstructed three-dimensional structure of the hyperplastic bile duct. By comparing contrast CT with pathological sections, it is proved that phase contrast CT is highly sensitive to cholangiography as a non-invasive imaging mode. By imaging samples of human biliary cirrhosis, It has been found that there are folds on the surface of the proliferative bile duct. The study shows that contrast CT can be used as an effective method to evaluate the morphological changes of bile duct hyperplasia in patients with biliary cirrhosis, in order to observe the changes of the proliferative bile duct during the development of hepatic fibrosis. On the basis of the above experiments, the bile duct ligation sample groups were added. In addition to the sham operation group and the bile duct ligation group 6 weeks after ligation, the bile duct ligation group included 4 weeks and 8 weeks after bile duct ligation. The number of liver samples in each group was 8. Three dimensional structure of hepatic vascular tree was reconstructed by 9 渭 m resolution imaging of liver samples. In this study, contrast CT and high resolution 3D visualization were combined. The structure of the hyperplastic bile duct at different time points in the development of hepatic fibrosis was reconstructed. Based on the three-dimensional structure, the density and fractal dimension of the proliferative bile duct were quantitatively analyzed. The change mechanism of portal pressure in bile duct ligation model was preliminarily discussed. The results showed that the density of three dimensional vessels increased gradually with the development of fibrosis, and the ratio of fiber area increased gradually. The number of proliferative bile ducts and the number of arteries are increasing. The loss of small branches of portal vein, the proliferation of bile duct, and the deposition of collagen fibers can increase the pressure of portal vein, but in the case of suspected arterial vascular adhesion and fusion, Under the action of venous anastomotic branch and suspected expansion and proliferation of lymphatic vessels, The contrast CT technique provides a new method and direction to evaluate the development of hepatic fibrosis disease by using microvascular changes.
【学位授予单位】：天津医科大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：R575.2;R816.5

【参考文献】