【作者】 张博书；

【导师】 王明泉；

【作者基本信息】 中北大学 ， 信号与信息处理， 2008， 硕士

【摘要】 在当前的临床实践中,数字血管减影技术是一种有效的血管可视化工具。特别是近年来,基于平板成像器件的数字血管减影技术逐渐取代了传统的胶片和影像增强器型减影技术,成为医疗诊断中必不可少的工具。如何使减影更加清晰也成了近年来研究的热点。本文以平板探测器型DSA为主要研究对象,比较了基于平板成像器件的DSA和基于影像增强器件的DSA的主要差别,通过结果可以看到平板成像DSA具有很大的显影优势。在数字血管减影的研究上,对于成像条件比较好的DSA图像,可以使用直接减影的方法。但大部分DSA图像在进行减影时会受到背景器官的影响,因此本文采用了基于对数变换的减影方法,该方法使减影后的血管更加清晰可见。在减影的过程中,由于病人本身和人体器官不可避免的移动,使减影图像出现伪影。针对这种现象,本文介绍DSA图像中的配准技术,通过图像的配准尽量减少伪影对正常诊断的影响。根据血管图像的特点,采取特征点方法对图像进行配准。首先在造影图像上选取特征点,然后在原始图像上进行特征点偏移量的计算。在此基础上应用带有平滑参数的薄板样条插值方法,通过改变平滑参数来控制形变和平滑程度,从而对两幅图像进行配准。实验结果显示可以有效消除伪影。目前,绝大部分DSA图像都是满足DICOM3.0标准的,本文通过深入研究DICOM标准,来对DSA图像做正确的解析,并可以用VC++6.0实现DSA图像的显示。数字血管减影技术由于能够动态显示血管的流动情况,从而清晰显示病灶,提高疾病发现率与诊断的准确率,降低造影剂的使用,提高了手术的安全性,降低了手术成本,因此,其应用前景将十分广阔。更多还原

【Abstract】 In current clinic practice, Digital Subtraction Angiography (DSA) technique is an efficacious visualization tool for the blood vascular structures. Especially in recent years, Digital Subtraction Angiography technique gradually takes place of traditional film and image intensifier model DSA. And it becomes absolutely necessary tool in medical diagnosis. How to make subtraction more clear become of a research hotspot in the field of medical imaging in recently.The flat panel detector DSA is researched in this dissertation. The difference is compared with flat panel DSA and image intensifier DSA. By the experimental results, we can see that flat panel detector DSA has obvious advantage.In the study of DSA technique, the better image effect can use directly subtract method. But most of DSA image are affected by background organs in subtraction, so this paper use the logarithmic transformation subtraction method. This method makes the vascular image was subtracted more clearly. In the course of subtraction, the image appears artifacts because patient’s human organs inevitable moving. In this thesis, image registration problem in DSA technique is discussed and a new image registration approach is used. Firstly, the evenly chosen small number of points on the vascular centerlines forms the control points set. Secondly, control points offset is calculated in the mask image. Finally, a smoothed thin-plate splines (TPS) interpolation function is used to conduct image warping towards the mask image based on the corresponding control point sets. The smoothed thin-plate splines interpolation function can control the warping and smooth degree by adjusting the smooth parameter. The experimental results show this method can make the mask image registration. At present, most DSA image follows DICOM 3.0 Standard. In this dissertation the DSA image is displayed by research DICOM Standard, and a DSA image display software is developed by VC++6.0 programming.The DSA technique can dynamically display the vascular flowing condition, clearly display lesions, improve diseases discover-rate and diagnostic accuracy, which can decrease the contrast agent using, improve operation safety and reduce operation cost. In a word, the DSA technique will have extensive appliance and wide prospect.更多还原