Investigating the magnetic susceptibility properties of fresh human blood for noninvasive oxygen saturation quantification

Quantification of blood oxygen saturation on the basis of a measurement of its magnetic susceptibility demands knowledge of the difference in volume susceptibility between fully oxygenated and fully deoxygenated blood (??do). However, two very different values of ??do are currently in use. In this work we measured ??do as well as the susceptibility of oxygenated blood relative to water, ??oxy, by MR susceptometry in samples of freshly drawn human blood oxygenated to various levels, from 6 to 98% as determined by blood gas analysis. Regression analysis yielded 0.273 +/- 0.006 and -0.008 +/- 0.003 ppm (cgs) respectively, for ??do and ??oxy, in excellent agreement with previous work by Spees et al. (Magn Reson Med 2001;45:533542). Magn Reson Med, 2012. (c) 2011 Wiley Periodicals, Inc.