title: Multi-port-driven birdcage coil for multiple-mouse MR imaging at 7 T.
abstract: In ultra-high field (UHF) imaging environments, it has been demonstrated that multiple-mouse magnetic resonance imaging (MM-MRI) is dependent on key factors such as the radiofrequency (RF) coil hardware, imaging protocol, and experimental setup for obtaining high-resolution MR images. A key aspect is the RF coil, and a number of MM-MRI studies have investigated the application of single-channel RF transmit (Tx)/receive (Rx) coils or multi-channel phased array (PA) coil configurations under a single gradient coil set. However, despite applying a variety of RF coils, Tx (|B1+|)-field inhomogeneity still remains a major problem due to the relative shortening of the effective RF wavelength in the UHF environment. To address this issue, we propose a relatively smaller size of individual Tx-only coils in a multiple birdcage (MBC) coil for MM-MRI to image up to three mice. We use electromagnetic (EM) simulations in the finite-difference time-domain (FDTD) environment to obtain the |B1|-field distribution. Our results clearly show that the single birdcage (SBC) high-pass filter (HPF) configuration, which is referred to as the SBCHPF, under the absence of an RF shield exhibits a high |B1|-field intensity in comparison with other coil configurations such as the low-pass filter (LPF) and band-pass filter (BPF) configurations. In a 7-T MRI experiment, the signal-to-noise ratio (SNR) map of the SBCHPFconfiguration shows the highest coil performance compared to other coil configurations. The MBCHPFcoil, which is comprised of a triple-SBCHPFconfiguration combined with additional decoupling techniques, is developed for simultaneous image acquisition of three mice. SCANNING 38:747-756, 2016. © 2016 Wiley Periodicals, Inc.
authors.affiliation: Department of Health Science and Technology, Samsung Advanced Institute for Health Sciences and Technology, Sungkyunkwan University, Seoul, Korea.
authors.forename: Phil
authors.initials: P
authors.lastname: Heo
authors.affiliation: Neuroscience Research Institute, Gachon University, Incheon, Korea.
authors.forename: Jeung-Hoon
authors.initials: JH
authors.lastname: Seo
authors.affiliation: Neuroscience Research Institute, Gachon University, Incheon, Korea.
authors.forename: Sang-Doc
authors.initials: SD
authors.lastname: Han
authors.affiliation: Neuroscience Research Institute, Gachon University, Incheon, Korea.
authors.forename: Yeunchul
authors.initials: Y
authors.lastname: Ryu
authors.affiliation: Department of Mechanical and Biomedical Engineering, Gangwon University, Gangwon, Korea.
authors.forename: Jong-Deok
authors.initials: JD
authors.lastname: Byun
authors.affiliation: Neuroscience Research Institute, Gachon University, Incheon, Korea.|Department of Biomedical Engineering, Gachon University, Incheon, Korea.
authors.forename: Kyoung-Nam
authors.initials: KN
authors.lastname: Kim
authors.affiliation: Department of Health Science and Technology, Samsung Advanced Institute for Health Sciences and Technology, Sungkyunkwan University, Seoul, Korea.|Department of Radiology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.
authors.forename: Jung Hee
authors.initials: JH
authors.lastname: Lee
mesh_terms: D000818:Animals; D008279:Magnetic Resonance Imaging / Q000295:instrumentation*; D051379:Mice; D011846:Radio Waves; D059629:Signal-To-Noise Ratio
keywords: 7-T imaging; multiple birdcage coil; multiple-mouse MRI; radiofrequency