Is cortical grey matter diffusivity an early biomarker for neuronal damage?

There is growing evidence that pathological changes in Alzheimer’s disease (AD) begin several years before the symptom onset. Neuroimaging approaches can be used to detect microstructural alterations in the early stages of neurodegeneration using diffusion‐weighted MRI. Cortical grey matter mean diffusivity (cMD) is thought to be increased in AD following pathological alterations resulting in disrupted neuronal function, neuronal death and cellular atrophy. We hypothesised that changes in MD could be detected early in the disease progression and that they would be correlated with structural imaging biomarkers.