Linking neuron-axon-synapse architecture to white matter vasculature using high-resolution multimodal MRI in primate brain

Motivation: Mapping white matter vascularity is essential for understanding its role in brain function and disease, yet the organization of white matter vasculature remains poorly understood. Goal(s): We explore variability of vascularity in white matter and investigate its relationship with neuroanatomy. Approach: High-resolution ferumoxytol-weighted MRI was compared with diffusion MRI, T1w/T2w-FLAIR, in vitro neuron density, and receptor autoradiography in macaque monkeys. Results: We demonstrated the high inter-regional variability of vascularity in the superficial white matter, which was comparable to that in the gray matter, and the deep white matter. These variabilities are associated with myelin and synaptic densities. Impact: Submillimeter ferumoxytol-weighted MRI shows considerable potential to chart vascularity in white matter. The blood volume in white matter is linked to neuron-axon-synapse architecture.