Simultaneous FMRI and NIRS to Estimate Brain Cerebral Metabolism

The principal advantages of functional magnetic resonance imaging (fMRI) with blood-oxygenation- level-dependent (BOLD) contrast for studying brain function are: non-invasiveness, ubiquitous availability, relatively high spatiotemporal resolution, and the ability to map function over the entire brain. Thus, BOLD fMRI is the most widely applied technology to study healthy brain function and pathophysiology associated with disease. In studies of drug abuse and psychiatric illness though, normal assumptions mapping BOLD signals to neurometabolism may be violated. Generally, these effects are ignored, resulting in large study-to-study variability. Quantitative fMRI (qfMRI) measures metabolism directly and is more suitable for studies of drug abuse and psychiatric illness. However, qfMRI is too complex for routine use. Cerebral metabolism during brain activation during visual stimulation measured with a new fMRI approach that is simple enough for clinical applications will be compared to CMRO2 activation measured using standard qfMRI.