  Hemodynamic changes occur in stroke and neurodegenerative diseases.
Developing imaging techniques allowing the in vivo visualization and
quantification of cerebral blood flow would help better understand the
underlying mechanism of those cerebrovascular diseases. 3D ultrasound
localization microscopy (ULM) is a novel technology that can map the
microvasculature of the brain at large depth and has been mainly used until now
in rodents. Here, we demonstrated the feasibility of 3D ULM of the nonhuman
primate (NHP) brain with a single 256-channels programmable ultrasound scanner.
We achieved a highly resolved vascular map of the macaque brain at large depth
in presence of craniotomy and durectomy using an 8-MHz multiplexed matrix
probe. We were able to distinguish vessels as small as 26.9 {\mu}m. We also
demonstrated that transcranial imaging of the macaque brain at similar depth
was feasible using a 3-MHz probe and achieved a resolution of 60.4 {\mu}m. This
work paves the way to clinical application of 3D ULM.
