探头频率和声波能量对心肌背向散射积分测值的影响

摘要

目的 观察超声背向散射积分心动周期变化幅度(CVIB)测值与探头频率及发射声波能量(AP)的关系.方法 用HP-5500型超声诊断仪,取胸骨旁乳头肌短轴观,测量了32例正常人在不同探头频率和AP设置条件下,左室后壁心肌组织的CVIB值.结果 探头频率为2.0 MHz时,所测CVIB值较探头频率为3.0 MHz和4.0MHz时降低.AP过高(＞35 dB)或过低(＜20 dB)均使CVIB测值明显降低.结论 CVIB测值受探头频率和AP设置的影响,测量局部心肌组织的实际最大CVIB值需要选择恰当的探头频率和合理的AP设置.%Objective To investigate the influences of transducer frequency and acoustic power(AP)on the measurements of the magnitude of cyclic variation of integrated backscatter(CVIB).Methods On the left ventricular short axis view at papillary muscle level,the CVIB of posterior wall were measured with different transducer frequency and AP by HP-5500 ultrasonic instrument in 32 healthy volunteers.Results The values of CVIB measured by 2.0 MHz transducer were lower than those by 3.0 MHz and 4.0 MHz transducer(P＜0.01,respectively).Lower AP(＜20 dB),or excessive settings of AP(＞35 dB)induced a minimal CVIB.Conclusions The measurement of CVIB was influenced by the transducer frequency and AP,which have to be selected to measure the largest and more consistent actual CVIB of regional myocardium.