Sam Wharton1, Richard Bowtell1
1Sir Peter Mansfield
Magnetic Resonance Centre,
Recently, it was shown that the magnetic susceptibility of white matter has measurable anisotropy, but calculation of the full anisotropic susceptibility tensor requires a 6-parameter fit, using phase maps acquired at multiple orientations to B0. Here, we present a method for reducing the parameters in the fitting process to two, based on the assumption of cylindrical symmetry and a priori knowledge of the orientation of the principal axis of the susceptibility tensor. The 2-parameter method is demonstrated on simulated data and shown to require less sampling orientations and a smaller range of rotation angles compared to the 6-parameter method.