Evaluating kurtosis‐based diffusion MRI tissue models for white matter with fiber ball imaging. (13th January 2017) - Jensen, Jens H.
Abstract : In order to quantify well‐defined microstructural properties of brain tissue from diffusion MRI (dMRI) data, tissue models are typically employed that relate biological features, such as cell morphology and cell membrane permeability, to the diffusion dynamics. A variety of such models have been proposed for white matter, and their validation is a topic of active interest. In this paper, three different tissue models are tested by comparing their predictions for a specific microstructural parameter to a value measured independently with a recently proposed dMRI method known as fiber ball imaging (FBI). The three tissue models are all constructed with the diffusion and kurtosis tensors, and they are hence compatible with diffusional kurtosis imaging. Nevertheless, the models differ significantly in their details and predictions. For voxels with fractional anisotropies (FAs) exceeding 0.5, all three are reasonably consistent with FBI. However, for lower FA values, one of these, called the white matter tract integrity (WMTI) model, is found to be in much better accord with FBI than the other two, suggesting that the WMTI model has a broader range of applicability. Abstract : The predications from three different diffusion MRI tissue models of white matter for a specific microstructural parameter are compared with an independent measurement obtained with fiber ball imaging (FBI). In regions with high fractional anisotropy (FA), all three models are in good agreement with FBI. However, one of the models is found to perform better for lower FA regions and therefore may have a broader range of applicability.