Radio Frequency Coil for Dual-Nuclei MR Muscle Energetics Investigation Based on Two Capacitively Coupled Periodic Wire Arrays

Abstract

In this paper, we describe a dedicated radiofrequency coil for magnetic resonance imaging and spectroscopy (MRSI) at 4.7 T optimized for investigation of muscle energetics in a human forearm. The coil operating at the Larmor frequencies of protons 1 H (200.1 MHz) and phosphorous 31 P (81 MHz) is based on two cylindrical periodic structures made of thin metal wires with tips interconnected through structural capacities of printed overlapping patches and sliding electric contacts. By independently exciting two orthogonal eigenmodes of the structure, the coil can be tuned and matched at both frequencies without lumped capacitors and cover the target region of interest for the forearm flexor muscles.

Quadrature transceive wireless coil: Design concept and application for bilateral breast MRI at 1.5 T

“…Thus, a combination of two orthogonal modes (e.g., a butterfly mode and a surface mode combined at 4 T, 40,41 or a combination of two linearly polarized coils at 0.2 T 42 ) can significantly increase the transmit efficiency and receive sensitivity of a local coil. A combination of a volume mode and a surface mode of two capacitively coupled periodic parallel arrays of wires was used in an RF coil operating at the Larmor frequencies of protons and phosphorus at 4.7 T. 43 In this paper, we propose an improved alternative to the cable-connected local RF coils: a transceive (Tx/Rx) wireless coil operating in quadrature mode. The wireless coil design combines two types of linear resonators: a 'metasolenoid' resonator and a Helmholtz-type resonator.…”

“…Thus, a combination of two orthogonal modes (e.g., a butterfly mode and a surface mode combined at 4 T, 40,41 or a combination of two linearly polarized coils at 0.2 T 42 ) can significantly increase the transmit efficiency and receive sensitivity of a local coil. A combination of a volume mode and a surface mode of two capacitively coupled periodic parallel arrays of wires was used in an RF coil operating at the Larmor frequencies of protons and phosphorus at 4.7 T 43 …”