Modeling hyperoxia-induced BOLD signal dynamics to estimate cerebral blood flow, volume and mean transit time
Modeling hyperoxia-induced BOLD signal dynamics to estimate cerebral blood flow, volume and mean transit time
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DOI：
10.1016/j.neuroimage.2018.05.066
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发表时间：
2018-09-01
期刊：
影响因子：
5.7
通讯作者：
Pike, G. Bruce
中科院分区：
文献类型：
--
作者：
MacDonald, M. Ethan;Berman, Avery J. L.;Pike, G. Bruce
提出了一种获得脑血流灌注测量的新方法，利用血氧水平依赖(BOLD)MRI动态监测高氧诱导的脑血管内脱氧血红蛋白浓度的变化。使用动力学模型对数据进行处理，以得出脑血流(CBF)、脑血容量(CBV)和平均通过时间(MTT)等血流灌注指标。10名健康受试者连续进行BOLD序列成像，同时在高氧(70%O-2)状态下穿插正常氧基线时间段。BOLD信号的时间过程用指数摄取和衰减曲线来拟合，并且BOLD信号的生物物理模型被用来估计氧浓度函数。动脉输入函数由呼气末氧气测量得出，组织和动脉浓度函数之间的去卷积运算被用于计算CBF。根据估计的组织和动脉浓度函数的积分之比，计算CBV的静脉成分。脑血流量分别为61.6±-13.7和24.9±4.0ml100g(-1)min(-1)，静脉性脑血流量分别为1.83±-0.32和1.10±0.19ml100g(-1)，平均白质和灰质分别为2.94±-0.52和3.73±0.60ml100g(-1)。我们的结论是，通过分析在高氧时期获得的动态BOLD功能磁共振成像，有可能在预期的生理范围内得出CBF、CBV和MTT值。
A new method is proposed for obtaining cerebral perfusion measurements whereby blood oxygen level dependent (BOLD) MRI is used to dynamically monitor hyperoxia-induced changes in the concentration of deoxygenated hemoglobin in the cerebral vasculature. The data is processed using kinetic modeling to yield perfusion metrics, namely: cerebral blood flow (CBF), cerebral blood volume (CBV), and mean transit time (MTT). Ten healthy human subjects were continuously imaged with BOLD sequence while a hyperoxic (70% O-2) state was interspersed with baseline periods of normoxia. The BOLD time courses were fit with exponential uptake and decay curves and a biophysical model of the BOLD signal was used to estimate oxygen concentration functions. The arterial input function was derived from end-tidal oxygen measurements, and a deconvolution operation between the tissue and arterial concentration functions was used to yield CBF. The venous component of the CBV was calculated from the ratio of the integrals of the estimated tissue and arterial concentration functions. Mean gray and white matter measurements were found to be: 61.6 +/- 13.7 and 24.9 +/- 4.0 ml 100 g(-1) min(-1) for CBF; 1.83 +/- 0.32 and 1.10 +/- 0.19 ml 100 g(-1) for venous CBV; and 2.94 +/- 0.52 and 3.73 +/- 0.60 s for MTT, respectively. We conclude that it is possible to derive CBF, CBV and MTT metrics within expected physiological ranges via analysis of dynamic BOLD fMRI acquired during a period of hyperoxia.