Paula L. Croal1,
Emma Louise Hall1, Ian D. Driver1, Susan T. Francis1,
Penelope A. Gowland1
1SPMMRC,
School of Physics & Astronomy, University of Nottingham, Nottingham,
Nottinghamshire, United Kingdom
The power law () relating blood oxygenation and tissue R2* is yet to be tested experimentally in humans. This is important as models and simulations do not accurately depict intravascular effects. Cross-field studies which use neuronal activation or hypercapnia are confounded by changes in CBV (ΔCBV) which also modulate R2*. Here, isocapnic-hyperoxia is used to measure the dependence of R2* on oxygenation, and the effect of ΔCBV simulated. Experimental and simulation results support a reduction of  with field strength. For a given field, β will not have a significantly impact on CMRO2 estimations within a normal physiological range.