DISCRIMINATION OF METABOLITE FROM LIPID AND MACROMOLECULE RESONANCES IN CEREBRAL INFARCTION IN HUMANS USING SHORT ECHO PROTON SPECTROSCOPY

Short-echo proton spectroscopy allows the noninvasive study of metabol ites, lipids, and macromolecules in stroke patients, but spectra are d ifficult to interpret and quantify because narrow metabolite peaks are added to a broad background of lipid and macromolecule peaks. ''Metab olite nulling'' was used to distinguish the lactate peak from underlyi ng lipid and macromolecule peaks. Increases in the Lipid and macromole cule peaks were initially observed within the region of infarction in all patients, and further increases in Lipid peaks were seen in five o f the six patients during the following 6 weeks. The initial high lact ate concentration decreases during the first 2 weeks after stroke, whe reas lipid and macromolecule signals show a persistent elevation durin g the same period. Differences in the time courses of the observed cha nges suggest that lipid, macromolecule, and lactate signals arise from more than one source.