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Updated: Jul 31, 2026
Cerebral Blood Oxygenation Measurement Based on Oxygen-dependent Quenching of Phosphorescence
Published on: May 4, 2011
Quantifying the microvascular origin of BOLD-fMRI from first principles with two-photon microscopy and an
Louis Gagnon1, Sava Sakadžić2, Frédéric Lesage3
1Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Charlestown, Massachusetts 02129, Harvard-MIT Division of Health Sciences and Technology, Cambridge, Massachusetts 02139, lgagnon@nmr.mgh.harvard.edu.
Abstract:
The blood oxygenation level-dependent (BOLD) contrast is widely used in functional magnetic resonance imaging (fMRI) studies aimed at investigating neuronal activity. However, the BOLD signal reflects changes in blood volume and oxygenation rather than neuronal activity per se. Therefore, understanding the transformation of microscopic vascular behavior into macroscopic BOLD signals is at the foundation of physiologically informed noninvasive neuroimaging. Here, we use oxygen-sensitive two-photon microscopy to measure the BOLD-relevant microvascular physiology occurring within a typical rodent fMRI voxel and predict the BOLD signal from first principles using those measurements. The predictive power of the approach is illustrated by quantifying variations in the BOLD signal induced by the morphological folding of the human cortex. This framework is then used to quantify the contribution of individual vascular compartments and other factors to the BOLD signal for different magnet strengths and pulse sequences.
