Simultaneous assessment of human brain functional hemodynamics by magnetic resonance and near-infrared imaging

Near-infrared spectroscopy is a relatively new imaging method, which can provide important information on concentrations of oxy-and deoxy-hemoglobin in cortical areas of the brain. We discuss the advantages of the integration of magnetic resonance and optical imaging techniques and present the results of our experimental study on the comparison of optical and fMRI signals obtained simultaneously on humans during functional activity and at rest. In all subjects we found a good collocation of the brain activity centers revealed by both methods. We also found a high temporal correlation between the BOLD signal (fMRI) and the deoxy-hemoglobin concentration (near-infrared spectroscopy) in the subjects who exhibited low fluctuations in superficial head tissues. The contamination of optical signals superficial tissue layers urgers applying algorithms of three-dimensional optical tomography