title: The intrinsic signal-to-noise ratio in human cardiac imaging at 1.5, 3, and 4 T.
abstract: Cardiac imaging is inherently demanding on the signal-to-noise performance of the MR scanner and may benefit from high field strengths. However, the complex behavior of the radiofrequency field in the human body at high frequencies makes model-based analyses difficult. This study aims to obtain reliable comparisons of the signal-to-noise profile in the human chest in vivo at 1.5, 3, and 4 T. By using an RF-field-mapping method, it is shown that the intrinsic signal-to-noise increases with the field strength up to 4 T with a less than linear relation. The RF field profile is markedly distorted at 4 T, and the onset of this distortion is dependent on the body size. The high power deposition and the consequences of the RF field distortion are discussed.
authors.affiliation: Laboratory of Cardiac Energetics, National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, Maryland 20892, USA.
authors.forename: H
authors.initials: H
authors.lastname: Wen
authors.forename: T J
authors.initials: TJ
authors.lastname: Denison
authors.forename: R W
authors.initials: RW
authors.lastname: Singerman
authors.forename: R S
authors.initials: RS
authors.lastname: Balaban
mesh_terms: D000465:Algorithms; D006321:Heart / Q000033:anatomy & histology* / Q000502:physiology; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008962:Models, Theoretical; D012815:Signal Processing, Computer-Assisted