Magnetic resonance imaging (MRI)-based diffusion methods can quantify water molecule diffusion within tissues and are used to measure microstructural changes due to neurodegeneration. In a recent issue of the Journal of Alzheimer’s Disease, Nakaya et al. report on the “Assessment of Gray Matter Microstructural Alterations in Alzheimer’s Disease by Free Water Imaging”. This study and others indicate that MRI diffusion methods, including free water imaging and diffusion tensor imaging, can reveal gray matter microstructural changes present in many AD-affected brain regions. These techniques are a valuable tool for multi-modal and longitudinal imaging studies that can offer insights into AD neurobiology.