Studying the effects of relaxation on estimates of white-matter microstructure with diffusion encoded measurements

Motivation: Biophysical models developed for diffusion magnetic resonance often disregard relaxation effects when estimating microstructure parameters. Goal(s): Show the impact of relaxation effects on the estimated parameters obtained from white-matter spinal cord data. Approach: A model for general gradient waveforms was implemented and employed for estimating parameters of white-matter compartments from mouse spinal cord data. The fits were performed for versions of the model with and without transverse relaxation effects. Results: The estimated parameters of white-matter microstructure show a strong dependence on the relaxation parameters. Impact: The implemented framework shows that relaxation effects greatly impact estimated micro-structure parameters in tissue, even if they are normalized by non diffusion-weighted data. Moreover, the implemented model can be employed to assess biases in previously presented frameworks