Ex Vivo Mouse Brain Microscopy at 15T with Loop-Gap RF Coil

TL;DR

This paper presents a novel loop-gap RF coil optimized for ex vivo mouse brain MRI at 15T, achieving the highest resolution for whole mouse brains with improved sensitivity and homogeneity compared to traditional coils.

Contribution

The authors designed and characterized a simple, high-performance loop-gap RF coil that significantly enhances resolution and sensitivity in ex vivo mouse brain MRI at ultra high fields.

Findings

Achieved 47 μm^3 resolution in 1.8 hours

Double the sensitivity compared to surface coils

Highest resolution for whole mouse brain to date

Abstract

The design of a loop-gap-resonator RF coil optimized for ex vivo mouse brain microscopy at ultra high fields is described and its properties characterized using simulations, phantoms and experimental scans of mouse brains fixed in 10% formalin containing 4 mM Magnevist. The RF (B1) and magnetic field (B0) homogeneities are experimentally quantified and compared to electromagnetic simulations of the coil. The coil's performance is also compared to a similarly sized surface coil and found to yield double the sensitivity. A three-dimensional gradient-echo (GRE) sequence is used to acquire high resolution mouse brain scans at 47 {\mu}m3 resolution in 1.8 hours and a 20x20x19 {\mu}m3 resolution in 27 hours. The high resolution obtained permitted clear visualization and identification of multiple structures in the ex vivo mouse brain and represents, to our knowledge, the highest resolution ever achieved for a whole mouse brain. Importantly, the coil design is simple and easy to construct.