Description

Magnetic resonance spectroscopy (MRS) is identical to MRI except that the metabolite signal, rather than the dominant water signal, is measured. Proton (1H) MRS and phosphorous (P) MRS are two powerful spectroscopy methods to measure metabolism in vivo. By using water suppression techniques, proton MRS can monitor levels of important brain metabolites and neurotransmitters such as N-acetylaspartate (NAA), creatine, choline, lactate, myo-inositol, glutamate, glutamine, gamma aminobutyric acid (GABA), and glutathione. P MRS can be utilized to measure energy phosphate metabolites of inorganic phosphate (Pi), phosphocreatine (PCr), adenosine diphosphate (ADP), and adenosine triphosphate (ATP) in brain and muscle. In addition, phosphocholine (PC), phosphoethanolamine (PE), glycerophosphocholine (GPC) and glyceophosphoethanolamine (GPE) can also be detected in brain tissues.\ This protocol proposes three main goals. First, to implement and optimize current proton and P MRS methods published in the literature for the imaging of metabolites in human brain and muscle. Second, to further develop new methods for use in similar brain and muscle MRS applications. Third, to exchange MRS data with other studies in order to provide data analysis and quality control for the studies under this, other NIH, or outside protocols. To develop and optimize in vivo MRS methods, 300 healthy volunteers will be recruited over a period of ten years. The subjects will be aged 18-65 years, and include representative numbers of males, females, and minorities. The experiments will be performed on the GE 3T, Siemens 3T and 7T MRI scanners located at the NIH In Vivo NMR Research Center. In the first portion of the study, a clinical MRI will be performed to ensure the subject has no abnormal brain conditions. In the second portion of the study, MRS scans will be performed in various system and pulse parameter combinations. No medications will be involved. Total scan time during the MRS scan will be one to two hours long. We expect to obtain high quality proton and/or phosphorous spectroscopy imaging from healthy volunteers that will help establish accurate and reliable spectroscopy methods for clinical investigators to perform non-invasive studies of psychiatric, neurological disorders, and other diseases in human brain or muscle.