Calibrating the BOLD signal during a motor task using an extended fusion model incorporating DOT, BOLD and ASL data

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• 作者：Meryem A. Yü ; cel^a ; ^{mayucel@nmr.mgh.harvard.edu} ; Theodore J. Huppert^b ; David A. Boas^a ; ^c ; Louis Gagnon^a ; ^c
• 关键词：fNIRS ; fMRI ; ASL ; CMRO2 ; BOLD calibration ; Multimodal imaging
• 刊名：NeuroImage
• 出版年：2012
• 期刊代码：83_10538119
• 类别：neu
• 出版时间：16 July, 2012
• 卷：61
• 期：4
• 页码：1268-1276
• 文件大小：1147 K

摘要

Multimodal imaging improves the accuracy of the localization and the quantification of brain activation when measuring different manifestations of the hemodynamic response associated with cerebral activity. In this study, we incorporated cerebral blood flow (CBF) changes measured with arterial spin labeling (ASL), Diffuse Optical Tomography (DOT) and blood oxygen level-dependent (BOLD) recordings to reconstruct changes in oxy- (螖HbO₂) and deoxyhemoglobin (螖HbR). Using the Grubb relation between relative changes in CBF and cerebral blood volume (CBV), we incorporated the ASL measurement as a prior to the total hemoglobin concentration change (螖HbT). We applied this ASL fusion model to both synthetic data and experimental multimodal recordings during a 2-s finger-tapping task. Our results show that the new approach is very powerful in estimating 螖HbO₂ and 螖HbR with high spatial and quantitative accuracy. Moreover, our approach allows the computation of baseline total hemoglobin concentration (HbT₀) as well as of the BOLD calibration factor M on a single subject basis. We obtained an average HbT₀ of 71 渭M, an average M value of 0.18 and an average increase of 13%in cerebral metabolic rate of oxygen (CMRO₂), all of which are in agreement with values previously reported in the literature. Our method yields an independent measurement of M, which provides an alternative measurement to validate the hypercapnic calibration of the BOLD signal.