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.

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