Giulietti G, et al. - Researchers performed this study to investigate the added value of histogram analysis applied to measures derived from diffusion tensor imaging (DTI) for detecting brain tissue differences between Alzheimer's disease (AD), mild cognitive impairment (MCI), and healthy subjects (HS). Axial diffusivity (AXD) of normal-appearing white matter (NAWM) could serve as an early marker of microstructural brain tissue changes occurring during the AD course. Furthermore, it could be useful for assessing disease progression.