Fraker T D, Bingle J F, Wilkerson R D, Klingler J W, Weaver M T, Andrews L T
Department of Medicine, Medical College of Ohio, Toledo 43699.
Am Heart J. 1988 Aug;116(2 Pt 1):398-406. doi: 10.1016/0002-8703(88)90612-6.
This study tests the hypothesis that acute myocardial ischemia induces a characteristic temporal variation in regional ultrasound amplitudes. Myocardial ischemia was created by circumflex coronary artery occlusion in seven closed-chest mongrel dogs. Ultrasound images were acquired prior to occlusion and post-occlusion on a phased-array two-dimensional system. Unprocessed ultrasound data from end-diastolic images were taken digitally for quantitative gray level analysis. Temporal variation in ultrasonic gray level of a nonischemic control region was compared to the temporal variation in gray level of the ischemic area. In the ischemic area, the average gray level for all seven dogs increased from 39.2 +/- 4.2 prior to occlusion to 42.5 +/- 4.9 at 15 minutes after occlusion, and then to 44.4 +/- 5.9, 45.3 +/- 6.2, and 47.0 +/- 6.0 at 30, 60, and 120 minutes, respectively (p less than 0.05 for control vs 15 minutes and 15 minutes vs 120 minutes). No significant changes in the average gray level of all seven dogs occurred in the nonischemic area from pre-occlusion to 2 hours post-occlusion (38.8 +/- 8.8, 38.4 +/- 8.0, 37.7 +/- 8.4, 37.8 +/- 8.5, and 38.0 +/- 8.2 for control, 15, 30, 60, and 120 minutes, respectively. These data show that regions of acute myocardial ischemia can be characterized by temporal variation in intramyocardial ultrasonic gray level, not only from the time before coronary occlusion to 15 minutes after occlusion, but also between 15 and 120 minutes in the post-occlusion period. Gray level values in nonischemic regions of the left ventricle are remarkably constant over time.
本研究检验了急性心肌缺血会导致局部超声振幅出现特征性时间变化这一假设。通过闭塞七只开胸杂种犬的回旋支冠状动脉来制造心肌缺血。在闭塞前和闭塞后，利用相控阵二维系统采集超声图像。从舒张末期图像中获取未经处理的超声数据，进行数字化定量灰度分析。将非缺血对照区域超声灰度的时间变化与缺血区域灰度的时间变化进行比较。在缺血区域，所有七只犬的平均灰度从闭塞前的39.2±4.2增加到闭塞后15分钟时的42.5±4.9，然后在30、60和120分钟时分别增加到44.4±5.9、45.3±6.2和47.0±6.0（对照与15分钟以及15分钟与120分钟相比，p均小于0.05）。从闭塞前到闭塞后2小时，所有七只犬的非缺血区域平均灰度无显著变化（对照、15、30、60和120分钟时分别为38.8±8.8、38.4±8.0、37.7±8.4、37.8±8.5和38.0±8.2）。这些数据表明，急性心肌缺血区域的特征在于心肌内超声灰度的时间变化，不仅在冠状动脉闭塞前到闭塞后15分钟之间，而且在闭塞后15至120分钟之间也是如此。左心室非缺血区域的灰度值随时间显著恒定。
