Vessel architecture imaging reveals microvascular rarefaction and capillary-to-arteriole shift in cerebral small...

In cerebral small vessel disease, clinical imaging markers such as white matter hyperintensities are often considered late-stage indicators, with limited understanding of (early) underlying microvascular alterations. This prospective, cross-sectional study utilized vessel architecture imaging to assess microvascular alterations in vivo in 40 patients with cerebral small vessel disease and 21 controls at 3T MRI. Quantitative measures for vessel density, radius, and vessel type composition were derived. Overall, patients had lower vessel density and larger microvessel radius than controls, while blood perfusion levels remained similar between groups. Moreover, a shift from capillaries to arterioles was observed in cortical gray matter and normal-appearing white matter in patients. White matter hyperintensities demonstrated lower vessel density and larger radii than normal-appearing white matter, with no difference in vessel type composition. Our findings support the role of microvascular rarefaction in the pathophysiology of cerebral small vessel disease. The remaining vascular network with relatively more larger or more dilated (arteriolar) blood vessels and less dense microvessels may reflect uneven flow patterns, leading to less efficient delivery of oxygen, nutrients, and removal of metabolic waste products. Vessel architecture imaging can provide an early biomarker in future trials on microvascular growth therapy.Clinical Trial Registration Information: Measuring the blood vessel density in patients with heart failure or reduced cognitive function of vascular origin: CRUCIAL. https://doi.org/10.1186/ISRCTN22301128. 848109.