Skyba D M, Jayaweera A R, Goodman N C, Ismail S, Camarano G, Kaul S
Cardiovascular Division, University of Virginia School of Medicine, Charlottesville.
Circulation. 1994 Sep;90(3):1513-21. doi: 10.1161/01.cir.90.3.1513.
The purpose of this study was to determine whether myocardial perfusion can be quantified with myocardial contrast echocardiography using left atrial (LA) injection of contrast.
Based on a series of in vitro and in vivo experiments, the optimal dose of sonicated albumin microbubbles injected into the LA for establishing a linear relation between video intensity and blood volume in the anterior myocardium was determined. In 10 open-chest dogs, myocardial blood flow (MBF) was augmented by increasing myocardial blood volume (MBV) with an intravenous infusion of phenylephrine HCl. In the presence of this drug, left anterior descending artery stenosis was produced, followed by release of stenosis, to change MBF within the anterior myocardium. MBV was calculated by dividing radiolabeled microsphere-derived MBF by microbubble transit rate. There was close coupling between MBF and MBV in the anterior myocardium during LA injection of contrast (y = 1.0x-0.03, SEE = 1.07, r = .92, P < .001). An excellent correlation was also noted between background-subtracted peak video intensity and MBV (y = 0.24x + 0.73, SEE = 0.36, r = .88, P < .001). On multivariate analysis, background-subtracted peak video intensity correlated best with MBV.
Myocardial perfusion can be quantified from time-intensity curves derived from the anterior myocardium after LA injection of contrast. Background-subtracted peak video intensity in this situation correlates closely with MBV. When MBV and MBF are closely coupled, such as during inotropic stimulation of the heart, background-subtracted peak video intensity also correlates closely with MBF. Since there are similarities in the models of LA and venous injections, these data indicate that it may be feasible to quantify myocardial perfusion with myocardial contrast echocardiography after venous injection of contrast.
本研究的目的是确定使用经左心房（LA）注射造影剂的心肌对比超声心动图是否能够对心肌灌注进行定量分析。
基于一系列体外和体内实验，确定了经左心房注射用于在前壁心肌中建立视频强度与血容量之间线性关系的超声处理白蛋白微泡的最佳剂量。在10只开胸犬中，通过静脉输注盐酸去氧肾上腺素增加心肌血容量（MBV）来提高心肌血流量（MBF）。在此药物存在的情况下，造成左前降支动脉狭窄，随后解除狭窄，以改变前壁心肌内的MBF。通过将放射性标记微球衍生的MBF除以微泡通过速率来计算MBV。在经左心房注射造影剂期间，前壁心肌中的MBF与MBV之间存在密切的相关性（y = 1.0x - 0.03，标准误 = 1.07，r = 0.92，P < 0.001）。在减去背景后的峰值视频强度与MBV之间也观察到了良好的相关性（y = 0.24x + 0.73，标准误 = 0.36，r = 0.88，P < 0.001）。在多变量分析中，减去背景后的峰值视频强度与MBV的相关性最佳。
经左心房注射造影剂后，可根据前壁心肌得出的时间 - 强度曲线对心肌灌注进行定量分析。在这种情况下，减去背景后的峰值视频强度与MBV密切相关。当MBV与MBF密切相关时，如在心脏的变力性刺激期间，减去背景后的峰值视频强度也与MBF密切相关。由于经左心房注射与静脉注射的模型存在相似性，这些数据表明经静脉注射造影剂后使用心肌对比超声心动图对心肌灌注进行定量分析可能是可行的。
