{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,9]],"date-time":"2026-10-09T02:34:31Z","timestamp":1791513271077,"version":"4.3.4"},"reference-count":41,"publisher":"Wiley","issue":"9","license":[{"start":{"date-parts":[[2026,7,21]],"date-time":"2026-07-21T00:00:00Z","timestamp":1784592000000},"content-version":"vor","delay-in-days":0,"URL":"http:\/\/onlinelibrary.wiley.com\/termsAndConditions#vor"},{"start":{"date-parts":[[2026,7,21]],"date-time":"2026-07-21T00:00:00Z","timestamp":1784592000000},"content-version":"tdm","delay-in-days":0,"URL":"http:\/\/doi.wiley.com\/10.1002\/tdm_license_1.1"}],"funder":[{"DOI":"10.13039\/501100005416","name":"Norges Forskningsr\u00e5d","doi-asserted-by":"publisher","award":["288164"],"award-info":[{"award-number":["288164"]}],"id":[{"id":"10.13039\/501100005416","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100004257","name":"Helse Vest","doi-asserted-by":"publisher","award":["F\u201011470"],"award-info":[{"award-number":["F\u201011470"]}],"id":[{"id":"10.13039\/501100004257","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":["analyticalsciencejournals.onlinelibrary.wiley.com"],"crossmark-restriction":true},"short-container-title":["NMR in Biomedicine"],"published-print":{"date-parts":[[2026,9]]},"abstract":"<jats:title>ABSTRACT<\/jats:title>\n                  <jats:p>\n                    Phosphorus magnetic resonance spectroscopy (\n                    <jats:sup>31<\/jats:sup>\n                    P\u2010MRS) enables noninvasive measurement of brain metabolism, yet its reproducibility in clinical settings remains unclear. We systematically assessed intrasession and intersession variability as well as interindividual differences of key phosphorus metabolites at 3\u2009T in healthy individuals and persons with Parkinson's disease under various experimental conditions. Intersession variability, as measured by coefficients of variation (CoVs) increased notably for longer scan intervals (~1\u2009year), and metabolite ratios from well\u2010resolved spectral signals (i.e., adenosine triphosphate [ATP], phosphocreatine [PCr], and intracellular inorganic phosphate [P\n                    <jats:sub>i<\/jats:sub>\n                    ]) exhibited consistently higher stability compared with ratios calculated from metabolite signals overlapping on the spectrum (e.g., total nicotinamide adenine dinucleotide [tNAD], as well as phosphate monoesters [PMEs] and phosphate diesters [PDEs]). Test\u2013retest variability ranged from ~5 to 25\u2009CoV%, where PCr, ATP\u2010\u03b1, and ATP\u2010\u03b3 were the most stable while glycerophosphocholine (GPC), glycerophosphoethanolamine (GPE), phosphoethanolamine (PE), and tNAD varied considerably. Interindividual variability was found to be higher than intraindividual variability for all metabolite ratios, ranging from ~9 to 33\u2009CoV%. By systematically quantifying intraindividual and interindividual variability, as well as providing explicit sample size recommendations, this study facilitates more reliable longitudinal and cross\u2010sectional clinical trials and translational studies of brain metabolism featuring\n                    <jats:sup>31<\/jats:sup>\n                    P\u2010MRS.\n                  <\/jats:p>","DOI":"10.1002\/nbm.70362","type":"journal-article","created":{"date-parts":[[2026,7,21]],"date-time":"2026-07-21T10:38:09Z","timestamp":1784630289000},"update-policy":"https:\/\/doi.org\/10.1002\/crossmark_policy","source":"Crossref","is-referenced-by-count":1,"title":["Metabolite\u2010Specific Reproducibility of Cerebral\n                    <sup>31<\/sup>\n                    P\u2010MRS at 3\u2009T: Implications for Clinical Research"],"prefix":"10.1002","volume":"39","author":[{"ORCID":"https:\/\/orcid.org\/0000-0001-7720-7542","authenticated-orcid":false,"given":"Magnus","family":"Svensen","sequence":"first","affiliation":[{"name":"Neuro\u2010SysMed, Norwegian Centre of Excellence for Clinical Research on Neurological Diseases Haukeland University Hospital  Bergen Norway"},{"name":"Department of Clinical Medicine University of Bergen  Bergen Norway"},{"name":"K.G. Jebsen Center for Translational Research in Parkinson's Disease University of Bergen  Bergen Norway"},{"name":"Mohn Medical Imaging and Visualization Centre, Department of Radiology Haukeland University Hospital  Bergen Norway"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Christian","family":"D\u00f6lle","sequence":"additional","affiliation":[{"name":"Neuro\u2010SysMed, Norwegian Centre of Excellence for Clinical Research on Neurological Diseases Haukeland University Hospital  Bergen Norway"},{"name":"Department of Clinical Medicine University of Bergen  Bergen Norway"},{"name":"K.G. 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Jebsen Center for Translational Research in Parkinson's Disease University of Bergen  Bergen Norway"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Nj\u00e5l","family":"Brekke","sequence":"additional","affiliation":[{"name":"Department of Radiology Haukeland University Hospital  Bergen Norway"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-2583-7571","authenticated-orcid":false,"given":"Alexander R.","family":"Craven","sequence":"additional","affiliation":[{"name":"Department of Clinical and Biological Psychology University of Bergen  Bergen Norway"},{"name":"Department of Clinical Engineering Haukeland University Hospital  Bergen Norway"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Erika Veslem\u00f8y","family":"Sheard","sequence":"additional","affiliation":[{"name":"Neuro\u2010SysMed, Norwegian Centre of Excellence for Clinical Research on Neurological Diseases Haukeland University Hospital  Bergen Norway"},{"name":"K.G. 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