Ex vivo mouse brain microscopy at 15T with loop-gap RF coil.

Area of Science:

• Magnetic Resonance Imaging
• Biomedical Engineering
• Neuroscience

Background:

• High-resolution imaging of ex vivo mouse brains is crucial for understanding neuroanatomy and pathology.
• Existing radiofrequency (RF) coils may limit achievable resolution and sensitivity in ultra-high field MRI.

Purpose of the Study:

• To design, characterize, and validate a loop-gap-resonator RF coil optimized for ex vivo mouse brain microscopy at ultra-high fields.
• To compare the coil's performance against standard surface coils and electromagnetic simulations.

Main Methods:

• Electromagnetic simulations were used to design and optimize the RF coil.
• Phantoms and fixed ex vivo mouse brains were scanned using the developed coil.
• RF (B1) and magnetic field (B0) homogeneities were experimentally quantified.
• High-resolution 3D gradient-echo (GRE) sequences were employed for data acquisition.

Main Results:

• The loop-gap-resonator coil demonstrated superior sensitivity, doubling the performance of a similarly sized surface coil.
• Experimental results closely matched electromagnetic simulations for field homogeneities.
• Achieved resolutions of (47 μm)³ in 1.8 hours and 20×20×19 μm³ in 27 hours.
• Enabled clear visualization and identification of multiple structures within the ex vivo mouse brain.

Conclusions:

• The designed loop-gap-resonator RF coil offers a simple, constructible, and highly effective solution for ultra-high field ex vivo mouse brain MRI.
• This coil facilitates unprecedented resolution for whole mouse brain imaging, advancing neuroanatomical studies.
• The achieved resolution represents a significant advancement in the field of high-resolution neuroimaging.