title: Four-channel surface coil array for sequential CW-EPR image acquisition.
abstract: This article describes a four-channel surface coil array to increase the area of visualization for continuous-wave electron paramagnetic resonance (CW-EPR) imaging. A 776-MHz surface coil array was constructed with four independent surface coil resonators and three kinds of switches. Control circuits for switching the resonators were also built to sequentially perform EPR image acquisition for each resonator. The resonance frequencies of the resonators were shifted using PIN diode switches to decouple the inductively coupled coils. To investigate the area of visualization with the surface coil array, three-dimensional EPR imaging was performed using a glass cell phantom filled with a solution of nitroxyl radicals. The area of visualization obtained with the surface coil array was increased approximately 3.5-fold in comparison to that with a single surface coil resonator. Furthermore, to demonstrate the applicability of this surface coil array to animal imaging, three-dimensional EPR imaging was performed in a living mouse with an exogenously injected nitroxyl radical imaging agent.
authors.affiliation: Division of Bioengineering and Bioinformatics, Graduate School of Information Science and Technology, Hokkaido University, North 14, West 9, Kita-ku, Sapporo 060-0814, Japan.
authors.forename: Ayano
authors.initials: A
authors.lastname: Enomoto
authors.forename: Miho
authors.initials: M
authors.lastname: Emoto
authors.forename: Hirotada
authors.initials: H
authors.lastname: Fujii
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Hirata
keywords: Array; CW-EPR imaging; Decoupling; Surface coil