從心臟斷層掃描重建肺動脈

Abstract

這篇論文的目的在重建肺動脈的幾何模型從心臟斷層掃描,這模型將用在動態流體力學分析,所以,此模型的表面必須足夠平滑,而且,其表面的網格必須是四方形的,這個工作困難的地方是z軸方向的解析度相對於x軸和y軸太低,這z軸解析度約為3mm,而x軸和y軸解析度約為0.3mm,我們提供一個方法去解決這個問題,這主要觀念是任何截面通過直圓柱中軸於一點為橢圓,而且,這橢圓的短軸就為此直圓柱的半徑,我們就利用此性質去得到重建此模型所需的資訊. 這個方法主要分為三大步驟: 1.我們用人工的方式去分割原肺動脈CT images為左右肺動脈,且使用一些影像處理在這些images上 2.我們估計左右肺動脈中軸任何點的位置和半徑從前一個步驟得到的images 3.我們使用前一個步驟所得到的幾何資訊去重建肺動脈模型,且要滿足先前的要求

The purpose of the paper is in order to reconstruct the geometric model of the pulmonary artery from CT images and the model will be used in the dynamic fluid analysis. So the model must satisfy some properties. For example, the surface of the model need to be enough smooth, meshes of the surface are rectangular and so on. The difficulty of the work is that the resolution of the z-axis is too lower then the resolution of the x-axis and y-axis. The resolution is about 3mm in the z-axis but the resolution is about 0.3mm in the x-axis and y-axis. We provide an approach to solve the problem. The major notion in this paper is that any cross section passing one point of the axis of the cylinder is ellipse and the length of the short axis is as same as the length of the radius of the cylinder. By this property, we can get the information that we need to reconstruct the model. The approach in this paper is divided into three major steps. First, we partition the pulmonary artery into two separate tubes, the left and right pulmonary artery, with the user interface and deal properly with these raw images. Second, we extract the geometric data of the left and right pulmonary artery, the approximate position and radius of any point of the 3D medial axis, from previous images. Third, we use these data to reconstruct the 3D model of the pulmonary artery and make the surface of the model satisfy previous request.