Fan, Audrey P.Govindarajan, Sindhuja T.Kinkel, R. PhillipMadigan, Nancy K.Nielsen, A. ScottBenner, ThomasTinelli, EmanueleRosen, BruceAdalsteinsson, ElfarMainero, Caterina2022-07-112014-10-29Fan, Audrey P., Sindhuja T. Govindarajan, R. Phillip Kinkel, Nancy K. Madigan, A. Scott Nielsen, Thomas Benner, Emanuele Tinelli et al. "Quantitative Oxygen Extraction Fraction from 7-Tesla MRI Phase: Reproducibility and Application in Multiple Sclerosis." Journal of Cerebral Blood Flow & Metabolism 35, no. 1 (2014): 131-139. DOI: 10.1038/jcbfm.2014.1870271-678X1559-7016https://nrs.harvard.edu/URN-3:HUL.INSTREPOS:37372555Quantitative oxygen extraction fraction (OEF) in cortical veins was studied in patients with multiple sclerosis (MS) and healthy subjects via magnetic resonance imaging (MRI) phase images at 7 Tesla (7 T). Flow-compensated, three-dimensional gradient-echo scans were acquired for absolute OEF quantification in 23 patients with MS and 14 age-matched controls. In patients, we collected T2*-weighted images for characterization of white matter, deep gray matter, and cortical lesions, and also assessed cognitive function. Variability of OEF across readers and scan sessions was evaluated in a subset of volunteers. OEF was averaged from 2 to 3 pial veins in the sensorimotor, parietal, and prefrontal cortical regions for each subject (total of ~10 vessels). We observed good reproducibility of mean OEF, with intraobserver coefficient of variation (COV)=2.1%, interobserver COV=5.2%, and scan–rescan COV=5.9%. Patients exhibited a 3.4% reduction in cortical OEF relative to controls (P=0.0025), which was not different across brain regions. Although oxygenation did not relate with measures of structural tissue damage, mean OEF correlated with a global measure of information processing speed. These findings suggest that cortical OEF from 7-T MRI phase is a reproducible metabolic biomarker that may be sensitive to different pathologic processes than structural MRI in patients with MS.en-USCardiology and Cardiovascular MedicineClinical NeurologyNeurologyJournal Article2022-07-1110.1038/jcbfm.2014.187