Ramtilak Gattu1, Z Latif2, Zhifeng Kou3, Ewart M. Haacke3, Randall R. Benson4
1Radiology, Wayne State University/MR Research Facility, Detroit, MI , USA; 2Radiology, Wayne State University/MR Research Facility, Detroit, MI, USA; 3MR Research Facility, Wayne State University, Detroit, MI, USA; 4Neurology, Wayne State University, Detroit, MI, USA
DTI Fractional Anisotropy (FA) is sensitive to white matter pathology. Maximal sensitivity to pathology requires understanding the MR parameters which affect both sensitivity to diffusion and FA. We investigated the effect of voxel size on FA in five healthy subjects using seven different voxel dimensions. Identical brain volumes were imaged in order to isolate the effect of resolution. We found a logarithmic relationship between voxel size and FA. The data suggest that it is necessary to use the same imaging resolution when comparing FA between time points or between subjects.