Unexpected BOLD Behavior at 11.7 Tesla: A Comparison of Experimental Data with the Integrative BOLD Signal Model

Joerg Ulrich Seehafer¹, Kamil Uludag², Daniel Kalthoff¹, Tracy Deanne Farr¹, Mathias Hoehn¹

Synopsis: This fMRI study presents experimental data and theoretical consideration about the unexpected BOLD behavior at high magnetic field strengths greater than 7.0 Tesla. Experimental SE- and GE-EPI data at 7.0 and 11.7 Tesla did not show an increase of BOLD contrast with field strength. The Integrative BOLD Signal Model delivers a possible explanation, namely the decrease of extravascular contributions from venules and arterioles. Furthermore, these predictions are compared to experimental data. It is shown, that the Integrative BOLD Signal Model can describe our data and is giving new perspectives to high field fMRI, which are of definite interest to future experiments.