背向散射积分评价冠心病介入治疗术后心肌灌注恢复特性

目的 应用背向散射积分(IBS)技术定量评价 PTCA支架植入术后心肌灌注的恢复特性。方法 选择 40 例PTCA支架植入术的患者,其中心肌缺血组和心肌梗死组各 20 例。用 IBS技术,于手术前、术后 3 天、1 个月和 3 个月测量支架植入血管所对应的供血心肌节段 IBS和 IBS的变化幅度(CVIB),测量左室射血分数(EF)、左室短轴缩短率(FS)、二尖瓣血流E/A值和左室等容舒张时间(IVRT)。结果 心肌缺血组和心肌梗死组心肌 IBS降低和CVIB升高分别出现在术后3天和1月。梗死组心肌EF值与FS值术后3次随访均较术前增加;缺血组心肌收缩功能的改善出现在术后3个月。缺血组和梗死组术后E/A增加,IVRT减小分别出现在术后3个月和 1 个月。缺血组和梗死组左室 EF分别与心肌的CVIB呈正相关(r值分别为0.546和0.537),与校正 IBS呈负相关(r值分别为-0.561 和-0.556)。结论 IBS技术可定量评价PTCA支架植入术后心肌的血供恢复和功能变化,心肌缺血和心肌梗死术后心肌灌注的改善各具特征。

Influence of Contractility on Myocardial Ultrasonic Integrated Backscatter and Cyclic Variation in Integrated Backscatter

To evaluate the effects of left ventricular contractility on the changes of aver age image intensity (AII) of the myocardial integrated backscatter (IB) and cyclic variation in IB (CVIB), 7 adult mongrel dogs were studied. The magnitude of AII and CVIB were measured from myocardial IB carves before and after dobuta mine or propranolol infusion. Dobutamine or propranolol did not affect the magnitude of AII (13.8±0.7 vs 14.7±0.5, P >0.05 or 14.3±0.5 vs 14.2±0.4, P >0.05). However, dobutamine produced a significant increase in the magnitude of CVIB (6.8±0.3 vs 9.5±0.6, P <0.001) and propranolol induced significant decrease in the magnitude of CVIB (7.1±0.2 vs 5.2±0.3, P <0.001). The changes of the magnitude of AII and CVIB in the myocardium have been demonstrated to reflect different myocardial physiological and pathological changes respectively. The alteration of contractility did not affect the magnitude of AII but induced significant change in CVIB. The increase of left ventricular contractility res ulted in a significant rise of the magnitude of CVIB and the decrease of left ventricular contractility resulted in a significant fall of the magnitude of CVIB.

探头频率和声波能量对心肌背向散射积分测值的影响

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 5 5 0 0型超声诊断仪 ,取胸骨旁乳头肌短轴观 ,测量了 3 2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 .0MHz时 ,所测CVIB值较探头频率为 3 .0MHz和 4.0MHz时降低。AP过高 ( >3 5dB)或过低 ( <2 0dB)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。