Brain macromolecules: In vivo measurement by proton magnetic resonance spectroscopy

New single- and multiple-volume in vivo proton magnetic resonance spectroscopy techniques detect signals from brain macromolecules and can separate them from overlapping small molecule resonances. In vitro and animal studies have identified these resonances as arising from cytosolic proteins and mobile lipids. Increased macromolecule signals from lipids have been detected in both subacute stroke and in active multiple sclerosis plaques that reflect tissue breakdown and, in conjunction with elevated lactate, can be used to monitor phagocytic cell activity. The ability to follow changes in brain lipids and proteins should help to elucidate biochemical abnormalities accompanying a variety of pathological conditions.