Magnetic resonance spectroscopy: Clinical applications

Localized in vivo magnetic resonance spectroscopy (MRS) is a noninvasive technique providing neurochemical information from a selected volume-of-interest (VOI) [1,2]. Hardware requirements for MRS are the same as for standard magnetic resonance imaging (MRI), although substantially different type of information can be gained by using specific software for data acquisition (pulse sequence) and data processing. High-resolution MRS has been routinely used for several decades in chemistry and biochemistry (under the acronym NMR, nuclear magnetic resonance spectroscopy) to elucidate the structure of biologically important chemical compounds in solutions. The new technology introduced by MRI, specifically, the magnetic field gradients, enabled spatial encoding and spatially selective excitation, which provided basic methodological tools for localized in vivo MRS. In general, MRS can be applied for any nuclei with nonzero magnetic moment (spin), but biological and medical applications are mostly limited to 1H, 13C, 19F, and 31P isotopes. MRS of hydrogen nuclei (protons, 1H) is the most common clinical application.