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Development of Parametric Imaging of Myocardial Perfusion Using Ultrasonic Microbubble Destruction

超声微泡破坏心肌灌注参数化成像的发展

基本信息

批准号：
12670675
负责人：
OHMORI Koji
金额：
$ 2.05万
依托单位：
Kagawa Medical University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2000
资助国家：
日本
起止时间：
2000 至 2001
项目状态：
已结题

项目摘要

We devised a new intermittent imaging employing an ultrasound pulsing sequence that utilized ultrasonic microbubble destruction to quantitate myocardial blood flow (MBF).We devised a new intermittent imaging employing an ultrasound pulsing sequence that utilized ultrasonic microbubble destruction to quantitate myocardial blood flow (MBF). We found that abrupt shortening of ultrasound pulsing interval (PI) in myocardial contrast echocardiography during intravenous microbubble infusion produces a decay of contrast intensity (CI) along frame number (f), which fit tell to a decay function SI=α×exp(-β×f)+γ. Our study in vitro using a flow model revealed that α and β thus obtained reflect flow transit velocity. Subsequently, we performed an in vivo study in which MBF in rats was successfully quantitated with the new parameters derived from this formula. By defining myocardial velocityas Vel=1/(β/HR), where HR is heart rate, and myocardial blood volume as Vol=α+γ, MBF is determined as VelxVol … More = [1/(β/HR)](α+γ). MBF thus determined exhibited a close correlation with microsphere-derived MBF at baseline, during pharmacological hyperemia, and during coronary stenoses.Finally, we validated this method in clinical settings. The parameters obtained with harmonic power Doppler and commercially available microbubbles for clinical use, we examined the usefulness of the pulsing sequence. The extent of CI decay produced by PI shortening from 1:10 to 1:1 end-systolic ECG trigger during intravenous microbubble infusion exhibited a similar decay. The extent of CI decay:α/(α+γ) was found useful in quantification of coronary vasodilator reserve, which allowed defection of significant coronary stenoses with a sensitivity of 93 % and a specificity of 85%. In addition, multi-frame trigger that emitted a burst of 4 rapid pulses was found useful in standardizing microbubble concentration in the myocardium. The time duration from the beginning of segmental myocardial opacification after bolus microbubble injection to the burst in which the last pulse resulted in no opacification was correlated with myocardial blood volume, and thus the myocardial viability evaluated by 201-thallium uptake in infarcted segments inpatients. Less

我们设计了一种新的间歇成像，采用超声脉冲序列，利用超声微泡破坏来定量心肌血流量（MBF）。我们设计了一种新的间歇成像，采用超声脉冲序列，利用超声微泡破坏来定量心肌血流量（MBF）。我们发现，在静脉微泡输注期间，心肌造影超声心动图超声脉冲间隔（PI）的突然缩短会产生沿帧数(f)的对比度强度（CI）衰减，其符合衰减函数SI=α×exp(-β×f)+γ。我们的体外流动模型研究表明，由此获得的α和β反映了流动的传输速度。随后，我们进行了一项体内研究，用该公式导出的新参数成功地定量了大鼠MBF。定义心肌速度为Vel=1/(β/HR)，其中HR为心率，心肌血容量为Vol=α+γ，则确定MBF为VelxVol…More = [1/(β/HR)]（α+γ）。由此确定的MBF在基线、药理学充血期间和冠状动脉狭窄期间与微球源性MBF密切相关。最后，我们在临床环境中验证了该方法。用谐波功率多普勒和市售微泡获得的参数用于临床，我们检验了脉冲序列的有效性。静脉微泡输注时收缩期终末心电图触发PI由1:10缩短至1:1，所产生的CI衰减程度也表现出类似的衰减。CI衰减程度：α/(α+γ)可用于量化冠状动脉血管扩张剂储备，其灵敏度为93%，特异性为85%。此外，多帧触发可发出4次快速脉冲，可用于规范心肌微泡浓度。微泡注射后开始出现节段心肌混浊到最后一次脉冲爆发无混浊的时间与心肌血容量相关，可通过住院患者梗死节段201-铊摄取评价心肌活力。少