Linka A Z, Sklenar J, Wei K, Jayaweera A R, Skyba D M, Kaul S
Cardiovascular Division, University of Virginia School of Medicine, Charlottesville, VA, USA.
Circulation. 1998 Nov 3;98(18):1912-20. doi: 10.1161/01.cir.98.18.1912.
We hypothesized that by using our newly defined method of destroying microbubbles and measuring their rate of tissue replenishment, we could assess the transmural distribution of myocardial perfusion.
We studied 12 dogs before and after creation of left anterior descending coronary artery stenoses both at rest and during hyperemia (n=62 stages). Microbubbles were administered as a constant infusion, and myocardial contrast echocardiography (MCE) was performed with the use of different pulsing intervals. The video intensity versus pulsing interval plots derived from each myocardial pixel were fitted to an exponential function: y=A(1-ebetat), where A reflects microvascular cross-sectional area (or myocardial blood volume), and beta reflects mean myocardial microbubble velocity. The product A . beta represents myocardial blood flow (MBF). Average values for these parameters were derived from the endocardial and epicardial regions of interest placed over the left anterior descending coronary artery bed. Radiolabeled microsphere-derived MBF was also measured from the same regions. There was poor correlation between radiolabeled microsphere-derived MBF and A-endocardial/epicardial ratios (EER) (r=0.46). The correlation with beta-EER was better (r=0. 69, P<0.01). The best correlation with radiolabeled microsphere-derived MBF-EER was noted with A . beta-EER (r=0.88, P<0. 01).
The transmural distribution of myocardial perfusion can be accurately assessed with MCE with the use of our newly described method of tissue replenishment of microbubbles after their ultrasound-induced destruction. In the model studied, an uncoupling of the transmural distribution of MBF and myocardial blood volume was observed during reversal of the MBF-EER.
我们推测，通过使用我们新定义的破坏微泡并测量其组织再填充率的方法，能够评估心肌灌注的透壁分布。
我们在12只犬身上研究了左前降支冠状动脉狭窄形成前后静息和充血状态下的情况（共62个阶段）。微泡通过持续输注给药，并使用不同的脉冲间期进行心肌对比超声心动图（MCE）检查。从每个心肌像素得出的视频强度与脉冲间期图拟合为指数函数：y = A(1 - e^(-βt))，其中A反映微血管横截面积（或心肌血容量），β反映心肌微泡平均速度。乘积A·β代表心肌血流量（MBF）。这些参数的平均值来自置于左前降支冠状动脉床的内膜和外膜感兴趣区域。还从相同区域测量了放射性微球衍生的MBF。放射性微球衍生的MBF与A-内膜/外膜比值（EER）之间的相关性较差（r = 0.46）。与β-EER的相关性较好（r = 0.69，P < 0.01）。与放射性微球衍生的MBF-EER相关性最好的是A·β-EER（r = 0.88，P < 0.01）。
使用我们新描述的微泡超声诱导破坏后组织再填充方法，MCE能够准确评估心肌灌注的透壁分布。在所研究的模型中，在MBF-EER逆转过程中观察到MBF和心肌血容量的透壁分布解偶联。
