Taylor A L, Collins S M, Skorton D J, Kieso R A, Melton J, Kerber R E
J Am Coll Cardiol. 1985 Oct;6(4):831-8. doi: 10.1016/s0735-1097(85)80491-5.
The purpose of this study was to determine the extent of regional variability of image echocardiographic amplitude (expressed as gray level variability) in contrast-enhanced two-dimensional echocardiographic images, and to assess the effect of such baseline gray level variability on quantitation of the coronary perfusion bed. In 10 anesthetized closed chest dogs, short-axis papillary muscle echocardiographic images were obtained during control preinjection conditions and during injection of three contrast agents into the left main coronary artery with and without circumflex artery occlusion. Regional echocardiographic amplitude variation was measured by computer-based videodensitometric analysis of mean gray levels in four myocardial regions after cavity (background) gray level subtraction. To determine the effect of regional gray level variability on quantitation of the coronary perfusion bed, the contrast-enhanced left anterior descending artery perfusion bed was measured by two methods. The circumferential method ignored myocardial contrast inhomogeneity by measuring the circumferential extent of contrast enhancement, whether or not the enhancement by contrast medium extended transmurally. The exact method measured only the area of myocardium actually enhanced by contrast medium, which often did not extend transmurally. The perfusion beds determined by the two echocardiographic methods were compared with the anatomic perfusion bed determined by postmortem barium-gelatin coronary arteriography. Regional gray levels varied qualitatively and quantitatively in the control state (before contrast injection), with lateral regions being less bright than axial regions. After injection of contrast medium, brightness increased in all regions, the axial regions brightening most.(ABSTRACT TRUNCATED AT 250 WORDS)
本研究的目的是确定在对比增强二维超声心动图图像中，图像超声心动图幅度的区域变异性（以灰度变异性表示）的程度，并评估这种基线灰度变异性对冠状动脉灌注床定量的影响。在10只麻醉的开胸犬中，在对照预注射状态下以及在左旋支动脉闭塞和未闭塞的情况下向左主冠状动脉注射三种造影剂期间，获取短轴乳头肌超声心动图图像。通过基于计算机的视频密度计分析，在减去心腔（背景）灰度后，测量四个心肌区域的平均灰度，以测量区域超声心动图幅度变化。为了确定区域灰度变异性对冠状动脉灌注床定量的影响，通过两种方法测量对比增强的左前降支动脉灌注床。圆周法通过测量对比增强的圆周范围来忽略心肌对比不均匀性，无论造影剂的增强是否透壁延伸。精确法仅测量实际由造影剂增强的心肌面积，而该面积通常不透壁延伸。将两种超声心动图方法确定的灌注床与死后钡明胶冠状动脉造影确定的解剖灌注床进行比较。在对照状态（对比剂注射前），区域灰度在质量和数量上存在差异，外侧区域比轴向区域亮度低。注射造影剂后，所有区域的亮度均增加，轴向区域增亮最多。（摘要截短于250字）
