Application of Magnetic Resonance Spectroscopy in the Mental Diseases of Schizophrenia and Autism

Magnetic Resonance Imaging (MRI) employs a strong static magnetic field, time changing magnetic fields and RF fields to produce diagnostic images whose grey levels represent the MR signal from hydrogen nuclei in tissue water molecules and hydrocarbon chains (fat). MRI can also been done with MR signals from hydrogen nuclei attached to other molecules, for example, neurotransmitters (Glutamate and GABA). Because these are present in only mM concentrations in the brain versus 100 M for tissue water, the resulting low signal to noise limits the spatial and temporal resolution below diagnostic requirements in individuals, but is sufficient for measuring biochemical abnormalities in psychiatric diseases in patient versus control groups. MR signals can also be measured from other nuclei with magnetic moments such as P, C, and Na. Because these nuclei have a weaker MR signal per nucleus than H, the spatial and/or temporal resolution is much poorer.