心肌声学造影定量急性心肌梗塞后心肌血流量的实验研究

摘要

Objective To evaluate the capability of myocardial contrast echocardiography (MCE) in quantitative measurement of myocardial perfusion.Methods Six open-chest dogs were studied 3 hours after acute left circumflex coronary occlusion by means of non-selective coronary contrast echocardiography.The sonicated 5% human albumin was used for MCE.Myocardial blood flow(MBF)was measured by radiolabeled microspheres.Background-subtracted time-intensity curves from MCE images in each segmental myocardium of the left ventricular short-axis view were derived and quantified using an off-line videodensitometric analysis system.Measurements of the curves included peak intensity(PI),area under the curve(AUC),half-time of descent(T1/2d)or ascent(T1/2a)and time to peak intensity(Tp).The results were compared with concomitant MBF.Results An excellent correlation was obtained between the index of relative perfusion(the ratio of MBF in the hypoperfused area to the perfused area)and the ratios of AUC or PI in the hypoperfused area to the perfused area(r=0.92 and 0.84 respectively,P<0.01).AUC and PI demonsrated a fair correlation with the absolute MBF(r=0.77 and 0.71 respectively,P<0.01),and could directly reflect changes in MBF.However,the remaining time parameters failed to correlate.Concl usions Regional myocardial perfusion can be accurately quantified by background-subtracted time-intensity curves derived from MCE images.Thus,it may be possible in the future to quantitatively assess collateral perfusion with MCE during coronary occlusion.%目的 评价心肌声学造影定量心肌梗塞心肌血流灌注的价值.方法 、对6条犬急性心肌梗塞模型进行心肌声学造影,采用自身对照的方法分析缺血区和非缺血区心肌显影时间.强度曲线各参数之比与心肌血流量的关系.结果 梗塞区时间-强度曲线各参数中,曲线下面积(AUC)和峰值强度(PI)与心肌相对血流量高度相关(r=0.92和0.84,P<0.01),与心肌绝对血流量相关性良好(r=0.77和0.71,P<0.01).不同水平心肌血流量间的AUC、PI均存在显著性差异(P均小于0.01),且随着血流量的减少而呈下降趋势.三项时间指标与心肌绝对血流量无直接关系.结论 心肌造影时间-强度曲线参数中的曲线下面积和峰值强度可准确定量心肌梗塞后局部心肌血流量.