Huppert Theodore J, Allen Monica S, Diamond Solomon G, Boas David A
Department of Radiology, University of Pittsburgh, UPMC Presbyterian, 200 Lothrop St., Pittsburgh, PA 15213, USA.
Hum Brain Mapp. 2009 May;30(5):1548-67. doi: 10.1002/hbm.20628.
Stimulus evoked changes in cerebral blood flow, volume, and oxygenation arise from responses to underlying neuronally mediated changes in vascular tone and cerebral oxygen metabolism. There is increasing evidence that the magnitude and temporal characteristics of these evoked hemodynamic changes are additionally influenced by the local properties of the vasculature including the levels of baseline cerebral blood flow, volume, and blood oxygenation. In this work, we utilize a physiologically motivated vascular model to describe the temporal characteristics of evoked hemodynamic responses and their expected relationships to the structural and biomechanical properties of the underlying vasculature. We use this model in a temporal curve-fitting analysis of the high-temporal resolution functional MRI data to estimate the underlying cerebral vascular and metabolic responses in the brain. We present evidence for the feasibility of our model-based analysis to estimate transient changes in the cerebral metabolic rate of oxygen (CMRO(2)) in the human motor cortex from combined pulsed arterial spin labeling (ASL) and blood oxygen level dependent (BOLD) MRI. We examine both the numerical characteristics of this model and present experimental evidence to support this model by examining concurrently measured ASL, BOLD, and near-infrared spectroscopy to validate the calculated changes in underlying CMRO(2).
刺激诱发的脑血流量、血容量和氧合变化源于对血管张力和脑氧代谢中潜在神经介导变化的反应。越来越多的证据表明，这些诱发的血流动力学变化的幅度和时间特征还受到脉管系统局部特性的影响，包括基线脑血流量、血容量和血液氧合水平。在这项工作中，我们利用一个基于生理学的血管模型来描述诱发血流动力学反应的时间特征及其与潜在脉管系统结构和生物力学特性的预期关系。我们将此模型用于高时间分辨率功能磁共振成像数据的时间曲线拟合分析，以估计大脑中潜在的脑血管和代谢反应。我们提供了证据，证明基于我们模型的分析可从联合脉冲动脉自旋标记（ASL）和血氧水平依赖（BOLD）磁共振成像估计人类运动皮层中脑氧代谢率（CMRO₂）的瞬态变化。我们研究了该模型的数值特征，并通过同时测量ASL、BOLD和近红外光谱来验证计算出的潜在CMRO₂变化，从而提供实验证据来支持该模型。
