Sagar K B, Agemura D H, O'Brien W D, Pelc L R, Rhyne T L, Wann L S, Komorowski R A, Warltier D C
Medical College of Wisconsin, Department of Medicine, Milwaukee 53226.
Cardiovasc Res. 1990 Jun;24(6):447-55. doi: 10.1093/cvr/24.6.447.
The aim was to study ultrasonic propagation properties of normal and ischaemic myocardium with a scanning laser acoustic microscope and to correlate these changes with ultrasonic backscatter.
Myocardial ischaemia was produced by total occlusion of left anterior descending coronary artery in anaesthetised open chest dogs. Myocardium supplied by left circumflex coronary artery served as normal control. IBR5, an optimum weighted frequency average (4-6.8 MHz) of the squared envelope of diffraction corrected backscatter, was measured in vivo. Ultrasonic attenuation coefficient, an index of loss per unit distance, the propagation speed and heterogeneity index were measured from normal and ischaemic regions with a scanning laser acoustic microscope which operates at 100MHz in vitro. Myocardial water content of normal and ischaemic myocardium was also estimated.
Were five anaesthetised mongrel dogs.
Attenuation coefficient of 33.8(SD4.2) dB.mm-1 in the ischaemic tissue was lower than 63.8(17.2) dB.mm-1 in the normal tissue (p less than 0.01). Ultrasonic speed was lower in ischaemic than normal myocardium at 1584(25) v 1612(35) m.s-1 (p less than 0.05). Heterogeneity index of 11(7) m.s-1 in the ischaemic region was lower than 14(8) m.s-1 in the normal region (27% reduction, p less than 0.05). IBR5 and myocardial water content were higher in the ischaemic than the normal myocardium: -37.2(SEM1.8) dB v -46.6(0.6) dB, (p less than 0.01) and 80.9(0.0)% v 78(0.2)%, (p less than 0.05) respectively.
Ultrasonic properties of the myocardium are significantly altered during acute ischaemia.
旨在用扫描激光声学显微镜研究正常和缺血心肌的超声传播特性，并将这些变化与超声背散射相关联。
在麻醉开胸犬中通过完全闭塞左前降支冠状动脉造成心肌缺血。由左旋冠状动脉供血的心肌作为正常对照。在体内测量IBR5，即衍射校正后向散射平方包络的最佳加权频率平均值（4 - 6.8MHz）。用在体外100MHz下工作的扫描激光声学显微镜测量正常和缺血区域的超声衰减系数（单位距离损失指数）、传播速度和异质性指数。还估算了正常和缺血心肌的心肌含水量。
五只麻醉的杂种犬。
缺血组织的衰减系数为33.8（标准差4.2）dB·mm⁻¹，低于正常组织的63.8（17.2）dB·mm⁻¹（p<0.01）。缺血心肌的超声速度低于正常心肌，分别为1584（25）对1612（35）m·s⁻¹（p<0.05）。缺血区域的异质性指数为11（7）m·s⁻¹，低于正常区域的14（8）m·s⁻¹（降低27%，p<0.05）。缺血心肌的IBR5和心肌含水量高于正常心肌：分别为 - 37.2（标准误1.8）dB对 - 46.6（0.6）dB，（p<0.01）和80.9（0.0）%对78（0.2）%，（p<0.05）。
急性缺血期间心肌的超声特性发生显著改变。
