Imaging small intracortical blood vessels at 64 μm in-plane resolution in macaque monkey brain in vivo using a large-bore 7T MRI scanner

Motivation: Hemodynamics of the cerebral cortex are shaped by vascular architecture; however, it remains challenging to study the small intracortical vascular anatomy in vivo. Goal(s): To test whether intracortical arterioles can be detected in vivo in non-human primates at 7 Tesla using a conventional human MRI scanner, and to study the organization of arterials and venules. Approach: After conducting time-of-flight (TOF) contrast simulations, optimized TOF-MRA images from macaques were acquired using a 7T large-bore MRI scanner with 64-μm in-plane resolution. Results: Intracortical arterioles and venules were reliably imaged and exhibited cortical area-specific differences in distribution. Imaging times were as fast as 10 minutes. Impact: Using a standard human 7T MRI scanner, we illustrate that micron-scale intracortical arterioles are detectable non-invasively in vivo in primates. We suggest similar methods can be used to study human microvascular organization in health and disease.