心肌超声造影心动图对高强度聚焦超声左心室心肌消融心肌坏死范围的评价

Myocardial contrast echocardiography evaluation of left ventricular myocardial lesion created by high intensity focused ultrasound

目的探讨心肌超声造影心动图评价高强度聚焦超声(HIFU)左心室心肌消融心肌坏死范围的可行性。方法新西兰兔9只,兔龄8～12个月,体质量(3.0±0.2)kg(2.8～3.5 kg)。HIFU治疗频率1.5 MHz,强度9.64 kW/cm2,脉冲照射方式,Ton=0.2 s、0.3 s,Toff=1.0 s、1.5 s,重复次数20次,靶区范围3 mm×2 mm。照射后行左心室心肌超声造影心动图,然后取下心脏,做2mm心肌切片,用2,3,5-三苯基氯化四氮唑(TTC)染色。测量造影剂充盈缺损面积及与之相对应心肌切片TTC染色心肌坏死面积,并计算其占整个心肌的面积百分比。结果造影剂充盈缺损面积百分比(13.7%±6.7%)与TTC染色心肌坏死面积百分比(15.5%±4.9%)间差异无统计学意义(P>0.05);两者间呈显著相关(r=0.94,P<0.05)。结论心肌超声造影心动图可用于评价HIFU左心室心肌消融心肌坏死范围。

Objective To investigate the feasibility of myocardial contrast echocardiography（MCE） in evaluating left ventricular myocardial lesion created by high intensity focused ultrasound（HIFU）.Methods Nine New Zealand rabbits,aged 8-12 months old,body weight（3.0 ± 0.2） kg（2.8-3.5 kg）,were performed left ventricular myocardial ablation by HIFU with operation frequency of 1.5 MHz,ultrasound intensity of 9.64 kW/cm2,pulse duration Ton = 0.2-second and 0.3-second at Toff = 1.0-second and 1.5-second intervals respectively.The repetition was 20 times,and the target size was set as 3 mm × 2 mm.After HIFU exposure,MCE was performed.The heart was taken out and 2 mm myocardial sections were made.Then 2,3,5-triphenyltetrazolium chloride（TTC） staining was conducted for lesion observation.The lesion area identified by MCE and TTC staining were measured and area percentage was calculated.Results There was no statistically significant difference in area percentage of lesion evaluation between MCE and TTC staining（13.7 % ± 6.7 % vs 15.5 % ± 4.9 %,P 0.05）,their relationship was significant（r = 0.94,P 0.05）.Conclusion It is demonstrated that the MCE could be used to evaluate the lesion size created by HIFU.