title: An inverted-microstrip resonator for human head proton MR imaging at 7 tesla.
abstract: As an extension of the previously developed microstrip transmission line (MTL) RF coil design, a high-frequency RF volume coil using multiple inverted MTL (iMTL) resonators for human head imaging at high magnetic field strength of 7 tesla (T) is reported. Compared to conventional MTL resonators, iMTL resonators can operate at higher frequency with lower losses and, thus, are suitable for designs of high-frequency RF volume coils with large coil size for human MR imaging and spectroscopy at high fields. An approach using capacitive terminations was analyzed and applied to the design of the iMTL volume coil for improving RF field homogeneity and broadening frequency-tuning range. A performance-comparison study was conducted between the prototype iMTL volume coil and a custom-built TEM volume coil at 7 T. The iMTL volume coil presents a comparable SNR and intrinsic B1 homogeneity to the TEM volume coil. Phantom and the human head images acquired using the iMTL volume coil are also presented. The proposed iMTL volume coil provides an efficient and alternative solution to design high-frequency and large-size volume coils for human MR applications at very high fields.
authors.affiliation: Center for Magnetic Resonance Research, Department of Radiology, the University of Minnesota, Minneapolis, MN 55455, USA. xlz@cmrr.umn.edu
authors.forename: Xiaoliang
authors.initials: X
authors.lastname: Zhang
authors.forename: Kamil
authors.initials: K
authors.lastname: Ugurbil
authors.forename: Robert
authors.initials: R
authors.lastname: Sainati
authors.forename: Wei
authors.initials: W
authors.lastname: Chen
mesh_terms: D001921:Brain / Q000033:anatomy & histology*; D004867:Equipment Design; D019544:Equipment Failure Analysis; D006257:Head / Q000033:anatomy & histology*; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000295:instrumentation* / Q000379:methods; D009682:Magnetic Resonance Spectroscopy / Q000295:instrumentation* / Q000379:methods; D008280:Magnetics / Q000295:instrumentation*; D019047:Phantoms, Imaging; D011522:Protons; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014159:Transducers
chemical_list: D011522:Protons