Distinct signatures of white matter damage in cerebral small vessel disease and Alzheimer’s disease: a fixel‐based analysis study

Alzheimer’s disease (AD) and cerebral small vessel disease (SVD) are the two main causes of age‐related cognitive decline and frequently co‐exist in memory clinic patients. White matter diffusion alterations have been described as key features of both diseases with different spatial patterns in AD and SVD. Biomarkers that capture and disentangle the effects of each disease on white matter integrity are of great need but are still lacking. Advanced diffusion MRI‐based techniques on the fixel level (fiber population within a voxel) yield promise, since one can derive measures of both fiber density and fiber bundle cross‐section (Dhollander et al., Neuroimage, 2021). In this multimodal imaging study, we assessed the ability of these fixel metrics to detect disease‐specific signatures of white matter fiber tract damage yielding the path towards personalized medicine.