Small‐animal, whole‐body imaging with metamaterial‐inspired RF coil

• Published in: NMR in biomedicine 2018-08, Vol.31 (8), p.e3952-n/a
• Main Authors: Zubkov, Mikhail, Hurshkainen, Anna A., Brui, Ekaterina A., Glybovski, Stanislav B., Gulyaev, Mikhail V., Anisimov, Nikolai V., Volkov, Dmitry V., Pirogov, Yury A., Melchakova, Irina V.
• Format: Article
• Language: English
• Subjects: Acquisition Methods; Animals; Applications, Computational electromagnetics; Biological products; Body; Brass plating; Capacitance; Coiling; Computer Simulation; Field of view; Hybridization; Image quality; Kidney - diagnostic imaging; Magnetic resonance imaging; Magnetic Resonance Imaging - instrumentation; Metamaterials; Methods and Engineering; Mice; Mice, Inbred BALB C; MR Engineering; Radio Waves; Receptive field; RF receive coils; RF transmit coils; Sensitivity; Signal-To-Noise Ratio; Simulation; Tubes; Whole Body Imaging
• ISSN: 0952-3480; 1099-1492
• DOI: 10.1002/nbm.3952

Particular applications in preclinical magnetic resonance imaging require 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 a parallel array of wires operating on the principle of eigenmode hybridization was used to produce a small‐animal imaging coil. The coil field distribution responsible for the coil field of view and sensitivity was simulated in an electromagnetic simulation package and the coil geometrical parameters were optimized for whole‐body imaging. A prototype coil was then manufactured and assembled using brass telescopic tubes with copper plates as distributed capacitance. Its field distribution was measured experimentally using the B1+ mapping technique and was found to be in close correspondence with the simulated results. The coil field distribution was found to be suitable for large field of view small‐animal imaging and the coil image quality was compared with a commercially available coil by whole‐body scanning of living mice. Signal‐to‐noise measurements in living mice showed higher values than those of a commercially available coil with large receptive fields, and rivalled the performance of small receptive field and high‐sensitivity coils. The coil was deemed to be suitable for some whole‐body, small‐animal preclinical applications. A high‐SNR method for performing whole‐body preclinical imaging on small animals is presented. The method employs a specifically designed tunable metamaterial‐inspired RF coil to increase the imaging quality. The coil performance is compared to other whole‐body imaging options and found to provide equal or better results.