DURING THE past decade, magnetic resonance spectroscopy (MRS) has proven useful in the evaluation of metabolic processes in living systems.1 In many diseases, metabolic changes are likely to precede anatomical ones, both in the natural course of the disease and as responses to treatment. Magnetic resonance spectroscopy is sensitive to the presence of several metabolites that provide a means for early detection of diseases and treatment responses. In neurological diseases, phosphorus MRS and proton MRS are 2 major methods used to evaluate muscle and central nervous system pathology.1 Magnetic resonance imaging can be considered a spectral localization method. It produces a spatial map of the anatomical and eventual pathological distribution of relative amounts of water and fat. Unlike magnetic resonance imaging, in MRS the data are acquired without the application of a space-encoding gradient. The pulse sequence produces a signal decay in which the spins are percussing at a frequency determined by the local magnetic field and ultimately by their chemical relationship with different compounds. A Fourier transformation changes this series of signals into a spectrum. Therefore, by using MRS it is possible to detect the concentration of different compounds in a particular region of interest (ie, brain or muscle).
Linfante I, Ashizawa T. Proton Magnetic Resonance SpectroscopyAn In Vivo Window to Study Neurodegenerative Disorders. Arch Neurol. 1999;56(12):1446-1447. doi:10.1001/archneur.56.12.1446