高机械指数联合高剂量造影剂行心肌声学造影的安全性研究

目的探讨高机械指数（MI）超声辐照联合高剂量国产超声造影剂心肌声学造影，对大鼠血流动力学及组织器官损伤情况的影响。方法20只正常SD大鼠，经颈静脉注射全氟丙烷人血白蛋白微球注射剂（1ml／kg），在造影模式下调节MI至最大（MI=1．9），采用R波触发，每6个心动周期一次。造影前后分别监测心率、心电图、血压、肌钙蛋白T，结束后取大鼠心、肝、肾进行病理检查。结果大鼠心率、血压、肌钙蛋白T测值在造影前后无明显变化（P〉0．05）；造影后心脏病理检查见轻微损伤（心肌纤维稍变粗，胞浆呈细颗粒状；间质血管扩张充血），肝、肾未见异常结构改变；一只大鼠在注射造影剂的过程中出现室性期前收缩，注射结束5min后恢复正常。结论在常规超声条件下高MI及高剂量造影剂心肌声学造影对正常实验大鼠血流动力学无明显影响，肌钙蛋白T升高不明显，病理示心肌轻微损伤，偶致短暂室性早搏，但短时间内可恢复正常。本实验证实，高MI联合高剂量国产声学造影剂行心肌声学造影对于正常大鼠是安全的。

The safety study of myocardial contrast echocardiography (MCE) by high MI combined with high dosage of contrast media

Objective To investigate the safety of MCE by high MI combined with high dosage of self- made ultrasound contrast media, and to investigate the effect on hemodynamics changes and the tissues injury in healthy rats. Methods The diluted perfluoropropane contained human albumin microspheres were injected to 20 rats intravenously at a dose of 1 mL/kg. Under the mode of contrast enhancement, the mechanical index （MI） was triggered by R wave of electrocardiogram （ECG） in the interval of 6 cardiac cycles, MI was adjusted to 1.9. The heart rate （HR）, blood pressure （BP）, electrocardiogram （ECG）, troponin T （cTnT） of 20 healthy SD rats were monitored before and after MCE. Then the heart, liver and kidney were taken for pathologic examination. Results There was no significant changes in HR and BP of rats before and after treatment（ P 〉 0.05）. And there was no significant difference in the measurement of cTnT before and after treatment（ P 〉 0.05）. Slight damage was found in heart pathologic examination, and no abnormal structure changes were found in liver and kidney. Premature ventricular contraction was observed in one rat during the treatment, while it returned to normal in 5 minutes. Conclusion Under the condition of routine ultrasound, there is no significant effect on the bemodynamics changes of SD rats by MCE with high MI and high dosage of contrast media, the eTnT increase is not obvious, heart muscle has slight injury, premature ventricular contraction happens occasionally, and returns to normal in a short time. This study indicates that MCE with high MI and high dosage of contrast media is safe in normal rats.