Mapping vascular network architecture in primate brain using ferumoxytol-weighted laminar MRI

Area of Science:

• Neuroimaging
• Neuroscience
• Radiology

Background:

• Brain vascular mapping is crucial for understanding neuroimaging, diagnostics, and neurology.
• Current methods face challenges in precisely mapping vasculature across regions and cortical layers.
• Limited understanding exists regarding neurometabolic factors influencing brain microvasculature.

Purpose of the Study:

• To investigate whole-brain vascular volume using advanced MRI techniques in macaque monkeys.
• To validate findings with existing data on vascular densities and compare with cytoarchitecture and neuronal metrics.
• To establish a link between neurometabolic factors and vascular network architecture in the primate brain.

Main Methods:

• Ferumoxytol-weighted laminar-resolution multi-echo gradient-echo imaging was employed.
• Cerebral blood volume (CBV) was mapped using the ferumoxytol-induced change in transverse relaxation rate (ΔR₂*).
• Data were mapped onto 12 equivolumetric laminar cortical surfaces and compared with published data.

Main Results:

• CBV varied threefold across the brain, with highest volumes in the inferior colliculus and lowest in the corpus callosum.
• Cortical CBV was higher in primary sensory areas and lower in association areas.
• CBV showed positive correlations with neuron density and negative correlations with receptor densities.

Conclusions:

• The study provides significant methodological and conceptual advancements for cerebrovascular MRI.
• Translaminar vascular network motifs suggest distinct energy supply needs based on cytoarchitecture.
• A clear linkage between neurometabolic factors and vascular network architecture in the primate brain was established.