基于动力学模型的 82 铷心脏正电子发射断层扫描动态序列的因子分析。
Kinetic model-based factor analysis of dynamic sequences for 82-rubidium cardiac positron emission tomography.
机构信息
National Cardiac PET Centre, University of Ottawa Heart Institute, Ontario, Canada.
出版信息
Med Phys. 2010 Aug;37(8):3995-4010. doi: 10.1118/1.3438474.
PURPOSE
Factor analysis has been pursued as a means to decompose dynamic cardiac PET images into different tissue types based on their unique temporal signatures to improve quantification of physiological function. In this work, the authors present a novel kinetic model-based (MB) method that includes physiological models of factor relationships within the decomposition process. The physiological accuracy of MB decomposed (82)Rb cardiac PET images is evaluated using simulated and experimental data. Precision of myocardial blood flow (MBF) measurement is also evaluated.
METHODS
A gamma-variate model was used to describe the transport of (82)Rb in arterial blood from the right to left ventricle, and a one-compartment model to describe the exchange between blood and myocardium. Simulations of canine and rat heart imaging were performed to evaluate parameter estimation errors. Arterial blood sampling in rats and (11)CO blood pool imaging in dogs were used to evaluate factor and structure accuracy. Variable infusion duration studies in canine were used to evaluate MB structure and global MBF reproducibility. All results were compared to a previously published minimal structure overlap (MSO) method.
RESULTS
Canine heart simulations demonstrated that MB has lower root-mean-square error (RMSE) than MSO for both factor (0.2% vs 0.5%, p < 0.001 MB vs MSO, respectively) and structure (3.0% vs 4.7%, p < 0.001) estimations, as with rat heart simulations (factors: 0.2% vs 0.9%, p < 0.001 and structures: 3.0% vs 6.7%, p < 0.001). MB blood factors compared to arterial blood samples in rats had lower RMSE than MSO (1.6% vs 2.2%, p =0.025). There was no difference in the RMSE of blood structures compared to a (11)CO blood pool image in dogs (8.5% vs 8.8%, p =0.23). Myocardial structures were more reproducible with MB than with MSO (RMSE=3.9% vs 6.2%, p < 0.001), as were blood structures (RMSE=4.9% vs 5.6%, p =0.006). Finally, MBF values tended to be more reproducible with MB compared to MSO (CV= 10% vs 18%, p =0.16). The execution time of MB was, on average, 2.4 times shorter than MSO (p < 0.001) due to fewer free parameters.
CONCLUSIONS
Kinetic model-based factor analysis can be used to provide physiologically accurate decomposition of (82)Rb dynamic PET images, and may improve the precision of MBF quantification.
目的
因子分析已被用作一种方法，根据其独特的时间特征将动态心脏 PET 图像分解为不同的组织类型，以提高生理功能的定量。在这项工作中，作者提出了一种新的基于动力学模型的（MB）方法，该方法在分解过程中包括因子关系的生理模型。使用模拟和实验数据评估 MB 分解的（82）Rb 心脏 PET 图像的生理准确性。还评估了心肌血流（MBF）测量的精度。
方法
使用伽马变量模型来描述（82）Rb 在动脉血从右心室到左心室的传输，使用单室模型来描述血液和心肌之间的交换。对犬和大鼠心脏成像进行了模拟，以评估参数估计误差。在大鼠中进行动脉血采样，在狗中进行（11）CO 血池成像，以评估因子和结构准确性。在犬中进行可变输注持续时间研究，以评估 MB 结构和整体 MBF 可重复性。将所有结果与先前发表的最小结构重叠（MSO）方法进行比较。
结果
犬心脏模拟表明，MB 在因子（0.2%对 0.5%，p < 0.001 MB 对 MSO，分别）和结构（3.0%对 4.7%，p < 0.001）估计方面的均方根误差（RMSE）均低于 MSO，与大鼠心脏模拟结果一致（因子：0.2%对 0.9%，p < 0.001 和结构：3.0%对 6.7%，p < 0.001）。MB 血液因子与大鼠动脉血样本相比，RMSE 低于 MSO（1.6%对 2.2%，p =0.025）。与狗中的（11）CO 血池图像相比，血液结构的 RMSE 没有差异（8.5%对 8.8%，p =0.23）。与 MSO 相比，MB 下的心肌结构更具可重复性（RMSE=3.9%对 6.2%，p < 0.001），血液结构也更具可重复性（RMSE=4.9%对 5.6%，p =0.006）。最后，与 MSO 相比，MB 下的 MBF 值更具可重复性（CV=10%对 18%，p =0.16）。由于自由参数较少，MB 的执行时间平均比 MSO 短 2.4 倍（p < 0.001）。
结论
基于动力学模型的因子分析可用于提供（82）Rb 动态 PET 图像的生理准确分解，并且可能提高 MBF 定量的精度。
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