Magnetic Resonance Characterization of General Compartment Size Distributions

INTRODUCTION The influence of molecular diffusion on the MR signal can be exploited to estimate compartment size distributions in heterogeneous specimens [1]. There has been recent interest in adopting this idea to characterize axon diameter distributions in white matter [2]. To this end, previous studies have assumed a known statistical distribution of compartment sizes (such as log-normal or gamma distributions). However, neural tissue does not necessarily conform to such parametric distributions. In this study, we describe an alternative strategy to measure all moments of the compartment size distribution directly from a single diffusion-weighted MR signal decay curve, hence obviating the assumed existence of a known parametric size distribution.