Exploring Orientation Dependence of T2* in White Matter by Extreme Rotation of the Human Head at 7 Tesla

Graham Wiggins¹, Chris Wiggins², Bei Zhang¹, Ryan Brown¹, Bernd Stoeckel³, Daniel K. Sodickson¹

At 7T, T2* weighted gradient echo imaging reveals unexpected contrast variation in white matter which appears to be associated with specific fiber bundles. The mechanism behind this variation has been debated, and it has been proposed that it may be caused by intrinsic properties of the fiber bundle such as degree of myelination or iron content, or that it depends on the orientation of the fiber bundles in relation to the main B0 field. With a novel coil system we obtain T2* maps in orientations 90 degrees apart and demonstrate that T2* depends strongly on orientation.