Robust frequency-dependent diffusional kurtosis computation using an efficient direction scheme, axisymmetric modelling and regularization

Abstract

Motivation: While diffusion MRI has proven to be valuable for studying tissue microstructure, there is a need to develop more sensitive and specific methods to detect microstructural changes at various spatial scales. Goal(s): To develop an acquisition and analysis scheme that can robustly compute frequency-dependent diffusional kurtosis metrics. Approach: Acquisition parameters such as a novel efficient direction scheme were presented along with an analysis pipeline that utilizes axisymmetric modelling, spatial regularization, and maximizes data usage. Results: We demonstrate the advantage of using the efficient scheme over conventional methods, and the analysis pipeline improves diffusional kurtosis map quality compared to conventionally used methods. Impact: We present an acquisition and analysis scheme that generates robust frequency-dependent diffusional kurtosis maps, which may offer increased sensitivity to cytoarchitectural changes that occur at various cellular spatial scales over the course of healthy aging, and due to pathological alterations.