Department of Radiology, Calgary, AB, Canada; Department of Clinical Neuroscience, Calgary, AB, Canada; Hotchkiss Brain Institute, University of Calgary, Calgary, AB, Canada; Seaman Family Magnetic Resonance Research Centre, Foothills Medical Centre, Alberta Health Services, Calgary, AB, Canada.
Department of Radiology, Calgary, AB, Canada; Department of Clinical Neuroscience, Calgary, AB, Canada; Hotchkiss Brain Institute, University of Calgary, Calgary, AB, Canada; Seaman Family Magnetic Resonance Research Centre, Foothills Medical Centre, Alberta Health Services, Calgary, AB, Canada; Montreal Neurological Institute, McGill University, Montreal, QC, Canada.
Neuroimage. 2018 Sep;178:461-474. doi: 10.1016/j.neuroimage.2018.05.066. Epub 2018 May 29.
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) 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 min for CBF; 1.83 ± 0.32 and 1.10 ± 0.19 ml 100 g 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.
提出了一种新的方法来获得脑灌注测量值，该方法使用血氧水平依赖（BOLD）MRI 动态监测脑血管中去氧血红蛋白浓度在高氧诱导下的变化。通过使用动力学模型处理数据，得出灌注度量，即：脑血流量（CBF）、脑血容量（CBV）和平均通过时间（MTT）。10 名健康人类受试者在 BOLD 序列连续成像的同时，穿插高氧（70% O）状态和正常氧基线期。BOLD 时间过程拟合指数吸收和衰减曲线，BOLD 信号的生物物理模型用于估计氧浓度函数。动脉输入函数来自呼气末氧测量，组织和动脉浓度函数之间的解卷积操作用于产生 CBF。CBV 的静脉成分从估计的组织和动脉浓度函数的积分比计算得出。平均灰质和白质测量值分别为：61.6 ± 13.7 和 24.9 ± 4.0 ml/100 g/min 的 CBF；1.83 ± 0.32 和 1.10 ± 0.19 ml/100 g 的静脉 CBV；以及 2.94 ± 0.52 和 3.73 ± 0.60 s 的 MTT。我们得出结论，通过分析高氧期间获得的动态 BOLD fMRI，可以在预期的生理范围内得出 CBF、CBV 和 MTT 度量。
