Algorithm effects on computerized vessel analysis from digitized cine film and a new method of generating the centerline of a vessel

This study concerns methods of accurately measuring vessel diameters using coronary cineangiograms. Various edge detection filters are compared and a new method for determining the centerline of a vessel is developed. Vessel phantoms of different sizes are used to evaluate the precision and accuracy of an entropy filter, a combined first and second derivative filter, a Laplace-Gaussian filter, a first derivative filter and a second derivative filter. The entropy filter is found to yield the most reliable, precise and accurate data. For use in a clinical case with an irregular arterial wall, a new method of determining the centerline is delineated in which the centerline of a vessel (which we define as a set of points having equal distance to each of any two opposite edge lines) is calculated with images called distance maps. We find that this method of detecting the centerline provides an acceptable assessment of the centerline on visual evaluation.     

Boundary detection and volume determination of the left ventricle from a cineangiogram

This paper is concerned with a method to detect left ventricular boundaries and the subsequent volume computation from a cineangiogram by a digital computer. It will first describe three digital techniques: (1) to restore the original dimensions by a logarithmic transformation; (2) to reduce noise by averaging images; and (3) to subtract images after and before dye injection, and then a boundary detection method based on statistical principles and heuristics. A method to locate the aortic valve will also be described.Experimental results on several cine frames will be presented to demonstrate the feasibility of these techniques. Once the boundary of the ventricle is determined, the computation of the volume is performed by the usual Simpson's rule.     

Automatic detection method of stenotic lesions in coronary cineangiograms

A new image processing procedure enabling the automatic detection of coronary artery stenoses by cineangiography was developed. Detection of stenoses was performed using computer image processing by the following procedure. The path of the arteries was extracted by a subtraction method. The thresholding image was obtained from the subtraction image, and converted to a thinning image, which represented the center line of the artery. For measurement of the arterial diameter, the vessel edges were determined by unilateral Gaussian fit to profile curves in sections perpendicular to the center line. Stenoses could then be detected on the basis of the normal diameter of artery estimated by Hough transformation. This method facilitates the detection of stenotic lesions from coronary cineangiograms.     

微机辅助多相位左室壁运动定量测定及其对冠心病的诊断价值

本研究在 LM-2000心脏医学图象处理系统的辅助下,应用多帧多相位定量测定法分析了17例正常人和24例冠心病患者节段性左室壁运动功能。结果表明,在正常左心室或冠心病组非缺血节段,相关系数 r 值和回归斜率 b 值高且其标准差小,在冠心病组的缺血节段,r 值和 b 值降低且其标准差增大(Pr<0.01,Pb<0.01)。分析180根辐射轴上室壁运动障碍的发生时相发现80%的辐射轴在收缩早期呈现室壁运动障碍,至收缩晚期仅见34%的辐射轴仍呈现室壁运动障碍。比较左心室整体功能参数(EF,1/3EF)及节段性室壁运动障碍指数(RI)与冠状动脉病变程度指数(CAI),发现 RI 与 CAI 关系最为密切。用 r 值和 b 值分析左心室节段性壁运动障碍具有高的敏感性及特异性。作者认为多帧多相位节段性左心室壁运动定量测定法能确切地反映缺血心肌运动异常的时空不一致性;r 值和 b 值是评价左心室壁运动障碍的敏感指标,其特异性也高。本法能用于定量诊断冠心病。