Mulvagh S L, Foley D A, Aeschbacher B C, Klarich K K, Seward J B
Division of Cardiovascular Diseases and Internal Medicine, Mayo Clinic and Mayo Foundation, Rochester, Minnesota, 55905, USA.
J Am Coll Cardiol. 1996 May;27(6):1519-25. doi: 10.1016/0735-1097(95)00619-2.
This study sought to evaluate the potential of second harmonic contrast echocardiography to assess coronary vasculature.
Newer transpulmonary ultrasound contrast agents capable of resonance phenomena detected by harmonic imaging may theoretically be able to demonstrate blood flow in the myocardium.
Transthoracic B-mode images and Doppler were obtained using a prototype second harmonic ultrasound system after femoral vein injection of AF0145 (10 to 40 mg) in 13 closed chest dogs (mean weight 25.6 kg). Coronary Doppler flow was simultaneously invasively measured using an intracoronary flow wire and visually compared with transthoracic Doppler flow. "Noninvasive" coronary vasodilator reserve was determined by measuring the ratio of the Doppler time velocity integral after adenosine to the baseline value and compared with the "invasive" intracoronary determination.
Harmonic imaging showed heterogeneous opacification of the myocardium characterized by linear branching structures consistent with intramyocardial coronary arteries, which were not clearly visible during conventional ultrasound imaging. In nine dogs, transthoracic Doppler was performed, and characteristic coronary Doppler flow was observed, identical to the simultaneously observed intracoronary Doppler flow. Intracoronary adenosine (120 to 150 microgram) equally increased intracoronary and transthoracic Doppler flow velocities. The calculated "noninvasive" and "invasive" coronary vasodilator reserve ratios were similar ([mean +/- SD] 3.3 +/- 1.0 and 3.6 +/- 1.2, p = NS), with excellent correlation (r = 0.95, p = 0.0012).
These findings indicate that noninvasive assessment of intramyocardial coronary vasculature and measurement of coronary blood flow reserve are possible using second harmonic contrast echocardiography.
本研究旨在评估二次谐波对比超声心动图评估冠状动脉系统的潜力。
能够通过谐波成像检测到共振现象的新型经肺超声造影剂理论上或许能够显示心肌内的血流情况。
在13只开胸犬（平均体重25.6千克）经股静脉注射AF0145（10至40毫克）后，使用原型二次谐波超声系统获取经胸B模式图像和多普勒图像。使用冠状动脉内血流导丝同时有创测量冠状动脉多普勒血流，并与经胸多普勒血流进行视觉比较。通过测量腺苷后多普勒时间速度积分与基线值的比值来确定“无创”冠状动脉血管扩张储备，并与“有创”冠状动脉内测定结果进行比较。
谐波成像显示心肌呈不均匀性显影，其特征为与心肌内冠状动脉一致的线性分支结构，在传统超声成像中无法清晰看到。在9只犬中进行了经胸多普勒检查，观察到了特征性的冠状动脉多普勒血流，与同时观察到的冠状动脉内多普勒血流相同。冠状动脉内注射腺苷（120至150微克）可同等程度增加冠状动脉内和经胸多普勒血流速度。计算得出的“无创”和“有创”冠状动脉血管扩张储备比值相似（[平均值±标准差]分别为3.3±1.0和3.6±1.2，p=无显著性差异），相关性良好（r=0.95，p=0.0012）。
这些发现表明，使用二次谐波对比超声心动图可以对心肌内冠状动脉系统进行无创评估并测量冠状动脉血流储备。
