Quantitation of normal cerebral metabolite levels with magnetic resonance spectroscopy and multifactorial meta analysis of the literature

Murat USLUQUANTITATION OF NORMAL CEREBRAL METABOLITE LEVELS WITHMAGNETIC RESONANCE SPECTROSCOPYANDMULTIFACTORIAL META ANALYSIS OF THE LITERATUREPURPOSE: To present, in a descriptive way, normal concentrations and ratios ofcerebral metabolites which were determined from healthy subjects in proton magneticresonance spectroscopic studies in literature. To define the effect of examination parameters,subject properties and anatomic region characteristics on the results and to provide controlgroup data for future studies.MATERIALS AND METHODS: A computer assisted literature search of theNational Library of Medicine?s Medline (PubMed) system was conducted to find proton MRSstudies of in vivo human brain, restricting dates for publications between 1996-August 2006.204 studies studying 3567 healthy subjects, which documented the number and age of thecontrol subjects, examination parameters and absolute concentrations of N-acetyl aspartate(NAA), choline (Cho), creatine (Cr), myo-inositol (mI) or metabolite ratios (NAA/Cr,NAA/Cho, Cho/Cr, mI/Cr), were included in the analysis. Weighted averages of absolutemetabolite concentrations and of metabolite ratios were calculated. These were analized aftergrouping for age and sex of the subjects, echo time (TE) and for the anatomic region studied.RESULTS: Results revealed from qualitative and quantitative studies of serebralproton MRS metabolites differ in a wide range in literature. Some of these differences dependon the properties of devices and subjects, parameters of proton MRS examination andanatomic region characteristics.