心肌梗死患者背向散射积分变化及临床意义

目的 探讨背向散射积分技术(IBS)定量评价心肌存活和左心室重构的临床应用。方法 记录18例健康志愿者和36例接受经皮冠脉支架置入术的初发急性心肌梗死患者的心尖左心室长轴、心尖四腔和两腔观超声背向散射图像，对比观察正常对照组与心肌梗死患者术后1周内、1个月及3个月时不同室壁节段心肌IBS值及其周期变异幅度(CVIB)的动态变化，并分析其与患者左心室形态及心功能改变之间的关系。结果 无左心室重构的A组，再灌注后1周内梗死与非梗死节段的IBS与正常组差异无显著性意义，梗死节段的CVIB较正常组明显减低；1个月及3个月时，CVIB随心功能恢复而逐渐改善。发生左心室重构的B组，再灌注后1周内梗死节段的IBS较正常组明显增高，梗死与非梗死节段的CVIB均显著减低；1个月及3个月时梗死与非梗死节段IBS均逐渐增高，而CVIB仅非梗死节段恢复。结论 心肌梗死患者的心肌背向散射积分参数与正常对照组明显不同，可作为评价心肌活性、预测左心室重构和心功能恢复程度的客观指标。

Changes and their clinical value of integrated backscatter in patients with acute myocardial infarction

Objective To explore the value of integrate d backscatter technique (IBS) in quantitative evaluation of myocardial viability and left ventricular remodeling (LVRM) in patients with acute myocardial infarction(AMI). Methods In 18 healthy subjects (control group) and 36 patients with first onset AMI, IBS images were obtained at apical long axis, 2- and 4-chamber views within one week, at 1 and 3 months after percutaneous intracoronary stenting. The dynamic changes of IBS and its cyclic variation (CVIB) at middle segments of six different walls of left ventricle were compared with normal control, and the relations of these changes with the remodeling and the function of left ventricle were analyzed. Results Based on the existence of LVRM, the patients were divided into two groups: group A without LVRM and group B with LVRM. In group A, IBS of both infarct and non-infarct segments were not significantly different from control group within one week while CVIB of infarct segments decreased significantly than that of control group. CVIB improved gradually with the recovery of LV function whereas IBS showed no change. In group B, IBS of infarct segments increased significantly than that of control group and CVIB of both infarct and non-infarct segments decreased significantly. IBS of both infarct and non-infarct segments increased gradually while only CVIB of non-infarct segments recovered. Meanwhile, ventricular aneurysm appeared and LV enlarged gradually with LV function not improved. Conclusions The dynamic changes of IBS are different in patients with AMI from normal subjects and it may be clinically useful to evaluate myocardial viability quantitatively and predict LVRM and the recovery of LV function.