Magnetic resonance spectroscopy of the human brain

Magnetic resonance (MR; synonymous with NMR = nuclear magnetic resonance) i s a universal physical technique best known for non-invasive detection and anatomical mapping of water protons (H). MR-spectroscopy (MRS) records prot ons from tissue chemicals other than water, intrinsic phosphorus containing metabolites, sodium, potassium, carbon, nitrogen, and fluorine, MRS is the refore an imaging technique with the potential to record human and animal b iochemistry in vivo. As a result of wide availability of MRI equipment in r esearch laboratories and hospitals, MRS is a serious competitor with PET to define normal body composition and its perturbation by pharmacological and pathological events. This article describes practical aspects of in vivo M RS with particular emphasis on the brain, where novel metabolites have been described. A survey of these new aspects of neurochemistry emphasize their practical utility as neuronal and axonal markers, measures of energy statu s, membrane constituents, and osmolytes, as well as some xenobiotics, such as alcohol. The concept of multinuclear in vivo MRS is illustrated by diagn osis and therapeutic monitoring of several human brain disorders. Although these methods are currently most frequently encountered in human studies, a s well as with transgenic and knockout mouse models, MRS adds a new dimensi on to anatomic and histopathologic descriptions. Anat Rec (New Anat) 265:54 -84, 2001. (C) 2001 Wiley-Liss, Inc.