Please use this identifier to cite or link to this item: https://ahro.austin.org.au/austinjspui/handle/1/9883
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dc.contributor.authorWellard, R Marken
dc.contributor.authorBriellmann, Regula Sen
dc.contributor.authorJennings, Claireen
dc.contributor.authorJackson, Graeme Den
dc.date.accessioned2015-05-15T23:09:25Z
dc.date.available2015-05-15T23:09:25Z
dc.date.issued2005-03-01en
dc.identifier.citationAjnr. American Journal of Neuroradiology; 26(3): 585-90en
dc.identifier.govdoc15760870en
dc.identifier.otherPUBMEDen
dc.identifier.urihttp://ahro.austin.org.au/austinjspui/handle/1/9883en
dc.description.abstractPhysiologic and scanner variability of proton MR spectroscopy (MRS) measurements can limit the detection of subtle metabolite fluctuations. We assessed the variability of such measurements at 3T and compared two methods to obtain absolute concentrations.Variability over 14 days was assessed with short-echo, single-voxel proton MRS in 14 control subjects and in a phantom containing 50 mmol/L N-acetylaspartate (NAA). Spectra were analyzed by using LCModel, scaling factors determined with both the calibration phantom (CP), and water peak intensity (WP) methods. Relative (reflecting the systematic drift) and absolute variability (reflecting the magnitude of scanner variability) was determined.For the phantom, initial (49 +/- 1.7 mmol/L) and second measurements (50 +/- 1.6 mmol/L) showed similar results, with small variability (relative, -0.6 +/- 1.5 mmol/L; absolute, 1.1 +/- 1.1 mmol/L). Control subjects had no systematic difference between the two scans for any measurement. Absolute variabilities in the temporal lobe for total NAA (NAA+NAAG) were 13% (CP) and 11% (WP). The largest variability (29%) was found for glutamate-glutamine (29%) with the CP method, and for myo-inositol with the WP method (28%). Absolute variability was smaller for the frontal lobe measurements (total NAA 7% and overall 6-18% for CP; total NAA 6% and overall 5-19% for WP). No significant difference was observed between the two methods.Physiologic variability is the major source of measurement variability and accounts for 12% of the variability in temporal lobe total NAA. Therefore, total NAA variations must clearly exceed this before they can reliably be attributed to an effect of disease.en
dc.language.isoenen
dc.subject.otherAdulten
dc.subject.otherAspartic Acid.analogs & derivatives.metabolismen
dc.subject.otherBrain.metabolismen
dc.subject.otherCalibrationen
dc.subject.otherFemaleen
dc.subject.otherFrontal Lobe.metabolismen
dc.subject.otherGlutamic Acid.metabolismen
dc.subject.otherGlutamine.metabolismen
dc.subject.otherHumansen
dc.subject.otherInositol.metabolismen
dc.subject.otherMagnetic Resonance Spectroscopyen
dc.subject.otherMaleen
dc.subject.otherModels, Biologicalen
dc.subject.otherOsmolar Concentrationen
dc.subject.otherPhantoms, Imagingen
dc.subject.otherReference Valuesen
dc.subject.otherReproducibility of Resultsen
dc.subject.otherTemporal Lobe.metabolismen
dc.subject.otherTime Factorsen
dc.titlePhysiologic variability of single-voxel proton MR spectroscopic measurements at 3T.en
dc.typeJournal Articleen
dc.identifier.journaltitleAJNR. American journal of neuroradiologyen
dc.identifier.affiliationBrain Research Institute, Austin Health, Melbourne, Australiaen
dc.description.pages585-90en
dc.relation.urlhttps://pubmed.ncbi.nlm.nih.gov/15760870en
dc.type.austinJournal Articleen
item.grantfulltextnone-
item.cerifentitytypePublications-
item.fulltextNo Fulltext-
item.openairetypeJournal Article-
item.openairecristypehttp://purl.org/coar/resource_type/c_18cf-
item.languageiso639-1en-
crisitem.author.deptNeurology-
crisitem.author.deptThe Florey Institute of Neuroscience and Mental Health-
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