Wankling P F, Perry R A, Seth A, Hunt A C, Escaned X, Newell J A, Shiu M F
Medical Physics Department, Queen Elizabeth Hospital, Birmingham, UK.
Int J Card Imaging. 1990;5(2-3):85-92. doi: 10.1007/BF01833977.
We have developed a low cost, clinically usable system for the objective assessment of the severity of coronary artery stenoses from single view angiograms. The system is based on a desktop computer with incorporated frame grabber. Images are captured by means of a video camera. The user selects a region of interest which encompasses the stenosis. Facilities are provided for automatic or manual definition of the artery centre line and edges. The computer then calculates the artery diameter and cross-sectional area by videodensitometry along profile lines which are orthogonal to the long axis of the artery. These results can be expressed numerically as a percentage stenosis when compared to a normal region of the artery. The image is corrected for geometric distortion using a grid test object. The image grey scale is corrected by means of a ramp test object such that a pixel value is proportional to the attenuator thickness. The ramp is placed on the patient during the X-ray examination and an iterative technique has been developed for subtracting the underlying structures from the superimposed ramp image. The system has been assessed using test objects constructed in Perspex which simulate arteries of known cross-sectional area and stenoses of known severity.
我们开发了一种低成本、临床可用的系统，用于从单视图血管造影客观评估冠状动脉狭窄的严重程度。该系统基于一台内置图像采集卡的台式计算机。图像通过摄像机采集。用户选择包含狭窄部位的感兴趣区域。提供了自动或手动定义动脉中心线和边缘的功能。然后，计算机通过沿与动脉长轴正交的轮廓线进行视频密度测定来计算动脉直径和横截面积。与动脉的正常区域相比，这些结果可以用数值表示为狭窄百分比。使用网格测试对象对图像进行几何失真校正。通过斜坡测试对象校正图像灰度，使像素值与衰减器厚度成比例。在X射线检查期间将斜坡放置在患者身上，并开发了一种迭代技术，用于从叠加的斜坡图像中减去底层结构。该系统已使用由有机玻璃制成的测试对象进行评估，这些测试对象模拟已知横截面积的动脉和已知严重程度的狭窄。
