The recent challenge in diffusion imaging is to find acquisition schemes and analysis approaches that can represent non-gaussian diffusion profiles in a clinically feasible measurement time. In this work we investigate the effect of b-value and the number of gradient vector directions on Q-ball imaging and the Diffusion Orientation Transform (DOT) in a structured way using computational simulat...

Introduction. There is a growing interest in parametric models to represent the diffusion-weighted signal [1-3] and to extend the common diffusion tensor imaging (DTI) model to better capture and characterize properties of the brain white matter (WM). Among them, a multi-fascicle model (MFM) which represents the signal contribution from each fascicle with a tensor and the freely diffusing water...

The fractional anisotropy (FA) value for Diffusion Tensor Imaging is widely used to determine the anisotropy of diffusion in a given voxel. As the FA value is based on the tensor’s eigenvectors it is not possible to calculate this quantity for HARDI diffusion profiles. In this paper we introduce an anisotropy index for HARDI data that utilizes the L-norm as the most natural notion of distance f...

Introduction Persistent angular structure (PAS) MRI [1] is one of many approaches that recover complex white matter fibre configurations within single voxels of high angular resolution diffusion MRI (HARDI) data. It continues to exhibit impressive performance compared to other state of the art methods [2], but at the expense of unreasonably long reconstruction times. Here, we propose and test a...

Introduction: The statistics of noisy MRI magnitude and root sum-of-squares (SoS) images are accurately modeled by the Rician and non-central chi (NCC) probability distributions, respectively [1]. In diffusion MRI (dMRI), the noise bias introduced by these distributions leads to distortion of estimated quantitative diffusion parameters [2]. One approach to addressing this noise bias is to denoi...

The choice of local HARDI reconstruction technique is crucial for discerning multiple fiber orientations, which is itself of substantial importance for tractography, and reliable and accurate assessment of white matter fiber geometry. Due to the complexity of the diffusion process and its milieu, distinct diffusion compartments can have different frequency signatures, making the HARDI signal sp...

Introduction: The resolution of diffusion weighted imaging (DWI) is mainly limited by hardware constraints and a negative relationship between image resolution and signal-to-noise ratio (SNR). Moreover, SNR can only to a limited extent be improved by repeating the measurements. Super-resolution (SR) is a technique that fuses information from a series of interpolated low resolution images to cre...