Ultrahigh Resolution Imaging of Zebrafish Embryos with a µMRI Insert in a Horizontal Bore Small Animal Scanner

Motivation: The absence of hardware specifically tailored for horizontal bore small animal MRI systems hinders the achievement of ultrahigh-resolution imaging. Goal(s): To facilitate volumetric imaging at sub 10³ µm³ spatial resolutions in a conventional horizontal small animal scanner. Approach: A custom-made high-performance gradient system and RF-hardware was interfaced to the system RF- and gradient-amplifiers, avoiding the requirement for specialized imaging software. A constant time imaging sequence was employed to capture ultrahigh-resolution images. Results: The setup was successfully tested for imaging of zebrafish embryos at different time points post fertilization with an isotropic spatial resolution of 9³ µm³. Impact: The suggested approach enables isotropic single-digit µm ultrahigh resolution imaging in conventional horizontal bore MRI systems. This supports novel imaging applications for a wide range of tiny animals, plants, or biological tissue without dedicated microscopy MR systems.