Effect of Phase Correction on DTI and q-space Metrics

International audienceThe non-Gaussian noise distribution, e.g. Rician, in magnitude Diffusion-Weighted Images (DWIs) can severely affect the estimation and reconstruction of the true diffusion signal. As a consequence, diffusion metrics computed on the estimated signal can be biased. We study the effect of phase correction, a procedure that re-establishes the Gaussianity of the noise distribution in DWIs by taking into account the corresponding phase images. We quantify the debiasing effects of phase correction in terms of diffusion signal estimation and calculated metrics. We perform in silico experiments based on a MGH Human Connectome Project dataset 3 and on a digital phantom, accounting for different acquisition schemes, diffusion-weightings, signal to noise ratios, and for metrics based on Diffusion Tensor Imaging (DTI) and on Mean Apparent Propagator Magnetic Resonance Imaging (MAP-MRI), i.e., q-space metrics. We show that phase correction is an effective tool to debias the estimation of diffusion signal and metrics from DWIs, especially at high b-values