DTI in the Clinic: Evaluating the Effects of Smoothing

Marta Moraschi¹, Gisela E. Hagberg², Giovanni Giulietti¹, Margherita Di Paola², Gianfranco Spalletta², Bruno Maraviglia³, Federico Giove³

We evaluated the effects of smoothing on the outcomes of a Diffusion Tensor Imaging (DTI) voxel-based analyses trying to separate differential effects between patients and controls. Gaussian smoothing introduced a high variability of results in clinical analysis, greatly dependent on the kernel size. On the contrary, anisotropic smoothing proved itself capable of maintaining boundary structures, with only moderate dependence of results on smoothing parameters. Our study suggests that anisotropic smoothing is more suitable in voxel based DTI studies; however, regardless of technique, a moderate level of smoothing seems to be preferable considering the artifacts introduced by this manipulation.