Evaluation of a quantitative blood oxygenation level‐dependent (qBOLD) approach to map local blood oxygen saturation

Abstract Blood oxygen saturation ( S O 2 ) is a promising parameter for the assessment of brain tissue viability in numerous pathologies. Quantitative blood oxygenation level‐dependent (qBOLD)‐like approaches allow the estimation of S O 2 by modelling the contribution of deoxyhaemoglobin to the MR signal decay. These methods require a high signal‐to‐noise ratio to obtain accurate maps through fitting procedures. In this article, we present a version of the qBOLD method at long TE taking into account separate estimates of T 2 , total blood volume fraction (BV f ) and magnetic field inhomogeneities. Our approach was applied to the brains of 13 healthy rats under normoxia, hyperoxia and hypoxia. MR estimates of local S O 2 (MR_L S O 2 ) were compared with measurements obtained from blood gas analysis. A very good correlation ( R 2 = 0.89) was found between brain MR_L S O 2 and sagittal sinus S O 2 . Copyright © 2010 John Wiley & Sons, Ltd.