脑房室模型的建立与脑血流的定量分析

为了简化无创的脑血流的定量方法,我们应用计算机仿真技术和以脉冲函数作为房室模型的输入函数,计算了24例患者脑99mTc-ECD时间-放射性曲线的脑存积分数.结果表明二室模型的脑存积分数R2和三室模型的脑存积分数R3在α=0.01水平上显著相关,相关系数为0.9836; 用R2和 R3计算脑血流量分别为29.48±1.51 和29.10±1.48 ml/min/100g, 两者之间无显著性差异(P＞0.05,n=24).这表明我们所提出的简化后的二室模型能够较好地刻划99mTc-ECD在脑内的分布机制,用脉冲函数作为模型的输入函数比用左心室的时间放射性曲线更为合适.

Set up Brain Compartment Model and Simplify CBF-quantification

In order to simplify the non-invasive quantitative evaluation of cerebral blood flow (CBF), we used computer simulation and adopted the pulse function as the input function of compartment model for calculting the mean retention fraction of 99mTc-ECD in brain from the time activity curves (n = 24). We found that there is a significant correlation between R2 (the retention fraction) from the 2-compartment model and R3 from the 3 compartment model with a correlation coefficient of 0.9836. The CBF by R2 is 29.48 +/- 1.51 ml/min per 100 g, the CBF by R3 is 29.10 +/- 1.48 ml/min per 100 g, and no significant difference between them is seen (P > 0.05, n = 24). These data indicate that the simplified two-compartment model for the mechanism of the uptake of 99mTc-ECD in brain is better. And we found that, compared with the entricular function, the pulse function may be used as a more appropriate input function for the model.