title: Linear response equilibrium.
abstract: A new periodic pulse sequence employing weak excitation is presented. This type of sequence drives the system into a steady-state with periodic time evolution from which the data can be reconstructed to a spectrum. It is demonstrated that the frequency response of such a sequence can be analyzed using perturbation methods and linear system analysis. A mathematical framework is proposed allowing the frequency response to be tailored by weighting a periodic flip function. The weak excitation level used implies very low specific absorption rates while generating a highly frequency selective signal in the order of 1/T2 with signal strengths comparable to those obtainable with conventional large flip angle balanced steady-state free precession techniques. The concept is illustrated with phantom experiments and in vivo feasibility of water fat separation is shown on human knee images.
authors.affiliation: Institute for Biomedical Engineering, University of Zurich and Swiss Federal Institute of Technology, Zurich, Switzerland.
authors.forename: Kai W
authors.initials: KW
authors.lastname: Eberhardt
authors.forename: Michael
authors.initials: M
authors.lastname: Schär
authors.forename: Christoph
authors.initials: C
authors.lastname: Barmet
authors.forename: Jeffrey
authors.initials: J
authors.lastname: Tsao
authors.forename: Peter
authors.initials: P
authors.lastname: Boesiger
authors.forename: Sebastian
authors.initials: S
authors.lastname: Kozerke
mesh_terms: D000273:Adipose Tissue; D001834:Body Water; D006801:Humans; D007091:Image Processing, Computer-Assisted; D007719:Knee Joint / Q000033:anatomy & histology*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D019047:Phantoms, Imaging