超声造影显像模式对实验兔心肌血管通透性的影响

目的观察心肌声学造影中，高机械指数诊断超声在连续发射及间歇触发条件下，对兔心肌血管通透性的影响。方法14只新西兰白兔随机分为两组：超声连续显像组和超声时间触发组。经耳缘静脉注射脂氟显微泡造影剂，0．5ml／kg。GE Vivid 7超声诊断仪，机械指数MI为1．3，采用连续显像和间隔2s触发显像方式作用于兔心脏。伊文思蓝（Evans blue，EB）作为血管通透性示踪剂。通过比较室性早搏的次数、EB心肌染色和漏出量、淤点淤斑的评分等指标，评价超声显像模式对心肌血管通透性的影响。结果诊断超声连续发射和间隔2s触发的条件下，出现的室性早搏次数无明显差异，但在触发条件下，出现多次的短阵室性心动过速，EB的漏出量较多（P〈0．01），EB透壁性较明显，视觉评分等级高于连续发射组（P〈0．01）。结论在心肌声学造影中，高MI诊断超声可以使兔心肌微血管通透性增高，间歇触发显像方式产生的生物学效应较显著。

Impact of imaging modalities on myocardial permeability in contrast echocardiography

Objective To explore the impact of continuous mode, time triggering mode on myocardial permeability in contrast echocardiography.Methods 14 New Zealand white rabbits were divided into two groups for the continuous imaging and time trigger imaging, respectively. Lipid microbubbles were injected intravenously at 0.5 ml/kg. GE Vivid 7 was used in the continuous and 2 s triggering imaging of rabbit's heart. The mechanic index was set at 1.3. Evans blue was injected as microvascular permeability's tracer. The myocardial permeability was assessed by using visual Evan's blue staining scores, counts of premature ventricular contractions (PVCs), petechial hemorrhages and Evans blue's quantification in myocardium.Results There was no significant difference on the PVCs counting between the continuous imaging and the time triggering imaging, but sisnificantly higher Evans blue staining visual scores (P<0.01) and higher Evans blue content (P<0.01) were found in the time triggering mode than that of the continuous mode. In addition, more ventricular tachycardia were detected in the triggering mode. Conclusion The diagnostic ultrasound can impact rabbit myocardial microvascular permeability during myocardial contrast echocardiography. The time triggering imaging mode tend to induce more biological effects than the continuous mode.