Fujii J, Sawada H, Aizawa T, Kato K, Onoe M, Kuno Y
Br Heart J. 1984 Feb;51(2):139-48. doi: 10.1136/hrt.51.2.139.
Left ventricular asynergy in myocardial infarction was assessed quantitatively by computer analysis of the cross sectional echocardiogram. Short axis cross sectional images of the left ventricle at the levels of the mitral valve, papillary muscle, and apex were recorded by a phased array sector scanner in 30 patients with healed myocardial infarction and 15 normal controls. Endocardial and epicardial short axis images of the left ventricle were transferred from video tape to a minicomputer through the interface circuits, then digitised and processed automatically by a minicomputer. Automatic edge detection of the endocardial and epicardial wall was performed by applying sequential steps including smoothing, second derivative technique, dynamic thresholding, and approximation of boundaries by a spline curve. To quantify regional wall motion, the short axis cross sectional left ventricular wall of each level was divided into eight octants with eight axes at 45 degrees angles from the initial standard axis which was constructed from the geometric centre of the end diastolic left ventricular cavity to the posterior end of the right side of the interventricular septum. Segmental hemiaxis, segmental area, segmental wall thickness, and those changes during cardiac cycle were measured and calculated in each segment automatically by a computer. Regional contractility of the left ventricle was evaluated by percentage systolic changes of the segmental hemiaxis, area, and wall thickness. These values were significantly reduced in the infarcted left ventricular wall as defined by left ventriculography and electrocardiography. Moreover, percentage hemiaxis changes obtained by quantitative left ventriculography described by Herman and colleagues correlated well with those using our analytical method of cross sectional echocardiography in the corresponding segments. The geometric centre of the left ventricular cavity determined by the computer moved slightly towards the anterior wall during systole in normal subjects, possibly reflecting the anterior swinging motion of the heart. The geometric centre of the left ventricular cavity in myocardial infarction moved towards the infarcted wall, showing that the floating reference system was inferior to the fixed reference system for the quantification of abnormal wall motion in myocardial infarction. In conclusion, a computer analysis of the short axis cross sectional echocardiogram of the left ventricle using the fixed reference system has shown its ability to evaluate left ventricular contraction abnormalities, especially systolic wall thickening, which is relatively free of arbitrary interpretation of the wall motion caused by the anterior swinging motion of the heart.
通过对横断面超声心动图进行计算机分析，对心肌梗死时的左心室协同运动进行了定量评估。用相控阵扇形扫描仪记录了30例陈旧性心肌梗死患者和15名正常对照者二尖瓣水平、乳头肌水平和心尖水平的左心室短轴横断面图像。左心室的心内膜和心外膜短轴图像通过接口电路从录像带传输到小型计算机，然后由小型计算机自动数字化和处理。通过应用包括平滑、二阶导数技术、动态阈值处理以及用样条曲线逼近边界等一系列步骤，对心内膜和心外膜壁进行自动边缘检测。为了量化局部室壁运动，将每个水平的左心室短轴横断面壁分成八个扇形区，从舒张末期左心室腔的几何中心到室间隔右侧后端构建初始标准轴，以该轴为基准每隔45度角设置八个轴。计算机自动测量并计算每个节段的节段半轴、节段面积、节段壁厚以及心动周期中的变化。通过节段半轴、面积和壁厚的收缩期变化百分比评估左心室的局部收缩性。如左心室造影和心电图所定义，梗死的左心室壁的这些值显著降低。此外Herman及其同事描述的定量左心室造影所获得的半轴变化百分比与我们在相应节段中使用横断面超声心动图分析方法所获得的结果具有良好的相关性。在正常受试者中，计算机确定的左心室腔几何中心在收缩期略向前壁移动，这可能反映了心脏的前向摆动运动。心肌梗死患者左心室腔的几何中心向梗死壁移动，表明在量化心肌梗死时异常室壁运动方面，浮动参考系统不如固定参考系统。总之，使用固定参考系统对左心室短轴横断面超声心动图进行计算机分析，已显示出其评估左心室收缩异常的能力，尤其是收缩期室壁增厚，相对而言不受心脏前向摆动运动引起的室壁运动的随意解释的影响。
