Small animal whole body imaging with metamaterial-inspired RF coil

Abstract

Preclinical magnetic resonance imaging often requires the entire body of an animal to be imaged with sufficient quality. This is usually performed by combining regions scanned with small coils with high sensitivity or long scans using large coils with low sensitivity. Here, a metamaterial-inspired design employing of a parallel array of wires operating on the principle of eigenmode hybridization is used to produce a small animal whole-body imaging coil. The coil field distribution responsible for the coil field of view and sensitivity is simulated in an electromagnetic simulation package and the coil geometrical parameters are optimized for the chosen application. A prototype coil is then manufactured and assembled using brass telescopic tubes and copper plates as distributed capacitance, its field distribution is measured experimentally using B1+ mapping technique and found to be in close correspondence with simulated results. The coil field distribution is found to be suitable for whole-body small animal imaging and coil image quality is compared with a number of commercially available coils by whole-body living mice scanning. Signal to noise measurements in living mice show outstanding coil performance compared to commercially available coils with large receptive fields, and rivaling performance compared to small receptive field and high-sensitivity coils. The coil is deemed suitable for whole-body small animal preclinical applications.