A Hybrid RF Coil for Whole-Brain Imaging in Non-Human Primates at 7 T

Area of Science:

• Neuroimaging
• Magnetic Resonance Imaging (MRI)
• Primate Neuroscience

Background:

• Ultra-high field MRI (≥7T) offers significant potential for detailed non-human primate (NHP) brain mapping.
• Existing systems face challenges with electromagnetic complexity and mechanical demands for awake NHP studies.

Purpose of the Study:

• To develop and validate a hybrid RF coil system for whole-brain functional MRI (fMRI) in macaques at 7 Tesla.
• To overcome the technical and mechanical challenges of ultra-high field imaging in awake NHPs.

Main Methods:

• A hybrid coil system combining a 6-channel transceive dipole array and a 16-channel loop receive array was designed.
• The system was optimized for awake imaging, ensuring compatibility with specialized primate chairs and head fixation.
• Electromagnetic simulations and phantom/in vivo experiments with anesthetized macaques validated the coil's performance.

Main Results:

• The hybrid coil achieved uniform B1+ distribution and supported parallel imaging with R=3x2 acceleration for high-resolution scans.
• Whole-brain functional MRI (fMRI) total signal-to-noise ratio (tSNR) was comparable to existing coils.
• Submillimeter resting-state fMRI demonstrated clear default-mode network connectivity.

Conclusions:

• The developed hybrid RF coil system effectively addresses ultra-high field MRI technical challenges and mechanical constraints for awake NHP studies.
• This system provides a powerful tool for advancing the understanding of primate brain function, particularly with visual stimulation.