Sagar K B, Pelc L R, Rhyne T L, Komorowski R A, Wann L S, Warltier D C
Department of Medicine, Medical College of Wisconsin, Milwaukee.
J Am Soc Echocardiogr. 1990 Nov-Dec;3(6):471-7. doi: 10.1016/s0894-7317(14)80363-5.
Tissue characterization reflects structural and functional integrity of tissues. Inasmuch as reversible ischemia causes no structural damage and irreversible ischemia results in persistent structural myocardial damage, we postulated that ultrasonic tissue characterization can distinguish the two types of injuries. Anesthetized open chest dogs underwent 15 minutes (group 1, n = 5) and 90 minutes (group 2, n = 8) of acute total occlusion of the left anterior descending coronary artery, followed by 3 hours of reperfusion. Myocardial ischemia-infarction was confirmed with segment shortening, electronmicroscopic examination, and triphenyl tetrazolium chloride staining. Integrated backscatter Rayleigh 5 (IBR5), a measure of ultrasonic backscatter, and Fourier coefficient of amplitude modulation (FAM), an index of cardiac cycle dependent variation in backscatter, were measured at baseline, during ischemia, and after reperfusion. Group 1 (reversible ischemia) showed an increase in IBR5 from -48 +/- 1.2 dB at control to -45 +/- 1.0 dB (p less than 0.01) during ischemia, which returned to baseline after reperfusion (-47 +/- 1.3 dB). FAM was blunted during ischemia (6.2 +/- 1.0 dB during control versus 1.2 +/- 1.0 dB during ischemia, p less than 0.01) and recovered completely during reperfusion. Segment shortening was abolished during ischemia (18% +/- 3% during control versus -12% +/- 5% during ischemia, p less than 0.01) and recovered partially during reperfusion (4% +/- 5%). The group 2 animals with irreversible myocardial injury showed an increase in IBR5, from -49 +/- 1.2 dB during control to -44 +/- 1.0 dB during ischemia (p less than 0.01) and paradoxical bulging of the ischemic region (17% +/- 3% to -7% +/- 3%, p less than 0.01) during ischemia.(ABSTRACT TRUNCATED AT 250 WORDS)
组织特征反映了组织的结构和功能完整性。由于可逆性缺血不会导致结构损伤，而不可逆性缺血会导致持续性心肌结构损伤，我们推测超声组织特征可以区分这两种类型的损伤。对麻醉开胸犬进行左前降支冠状动脉急性完全闭塞15分钟（第1组，n = 5）和90分钟（第2组，n = 8），随后再灌注3小时。通过节段缩短、电子显微镜检查和氯化三苯基四氮唑染色确认心肌缺血梗死。在基线、缺血期间和再灌注后测量超声背散射的一种测量指标——积分背向散射瑞利5（IBR5）以及背向散射中依赖心动周期变化的一个指标——幅度调制傅里叶系数（FAM）。第1组（可逆性缺血）在缺血期间IBR5从对照时的-48±1.2 dB增加到-45±1.0 dB（p<0.01），再灌注后恢复到基线水平（-47±1.3 dB）。FAM在缺血期间减弱（对照时为6.2±1.0 dB，缺血时为1.2±1.0 dB，p<0.01），在再灌注期间完全恢复。节段缩短在缺血期间消失（对照时为18%±3%，缺血时为-12%±5%，p<0.01），在再灌注期间部分恢复（4%±5%）。第2组有不可逆心肌损伤的动物在缺血期间IBR5增加，从对照时的-49±1.2 dB增加到缺血时的-44±1.0 dB（p<0.01），且缺血区域出现矛盾性膨出（从17%±3%到-7%±3%，p<0.01）。（摘要截断于250字）
