title: [1H magnetic resonance spectroscopy in intracranial tumors and cerebral ischemia].
abstract: Image-guided localized proton magnetic resonance can now increasingly be used with clinical 1.5T MR systems. To fuel the discussion on whether spectroscopy will become a routine modality or whether it will remain a research tool, we report on our experience with a stimulated echo sequence in 60 patients harboring intracranial tumors and 79 patients suffering from various forms of cerebral ischemia. Spectroscopy was incorporated into a routine imaging protocol, and the parameters of TR = 1500 ms, TE = 270 ms were kept constant over a 3-year period. Relative changes in the metabolite concentrations were estimated from peak height and area calculations compared with the spectra of 66 normal volunteers. The spectra of the volunteers did not show significant interindividual variations, and there were no changes during photic stimulation in a subgroup of 6 volunteers. All tumor patients' spectra were significantly different from those of normal controls. Low grade gliomas showed decreased levels of N-acetyl-aspartate and some had elevated levels of lactate. Oligodendrogliomas had higher choline levels than astrocytomas. High grade gliomas had higher levels of lactate and lower N-acetyl-aspartate ratios. Meningiomas were characterized by absence of N-acetyl-aspartate, and some metastases showed a lipid signal at 1 ppm. Spectra of ischemic brain tissue were also abnormal, revealing lowered N-acetyl-aspartate and elevated lactate. The changes paralleled the severity of ischemia and pronounced abnormalities were associated with an inferior outcome. Further technical improvements, including absolute quantification of metabolite concentrations and smaller sensitive volumes, will allow direct monitoring of treatment.(ABSTRACT TRUNCATED AT 250 WORDS)
authors.affiliation: Institut für Neuroradiologie der Universität des Saarlandes, Homburg.
authors.forename: S R
authors.initials: SR
authors.lastname: Felber
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001224:Aspartic Acid / Q000031:analogs & derivatives / Q000378:metabolism; D002545:Brain Ischemia / Q000175:diagnosis*; D002648:Child; D002675:Child, Preschool; D002794:Choline / Q000378:metabolism; D005260:Female; D005910:Glioma / Q000175:diagnosis / Q000378:metabolism; D006801:Humans; D007773:Lactates / Q000378:metabolism; D009682:Magnetic Resonance Spectroscopy; D008297:Male; D008577:Meningeal Neoplasms / Q000175:diagnosis / Q000378:metabolism; D008579:Meningioma / Q000175:diagnosis / Q000378:metabolism; D008875:Middle Aged; D009837:Oligodendroglioma / Q000175:diagnosis / Q000378:metabolism; D015173:Supratentorial Neoplasms / Q000175:diagnosis* / Q000378:metabolism
chemical_list: D007773:Lactates; D001224:Aspartic Acid; C000179:N-acetylaspartate; D002794:Choline
vernacular_title: 1-H-Magnetresonanzspektroskopie bei intrakraniellen Tumoren und zerebralen Ischämien.