title: A method to measure arbitrary k-space trajectories for rapid MR imaging.
abstract: A method to measure arbitrary k-space trajectories was developed to compensate for nonideal gradient performance during rapid magnetic resonance (MR) imaging with actively or nonactively shielded gradients at a magnetic field strength of 4.1 T. Accurate MR image reconstruction requires knowledge of the k-trajectory produced by the gradient waveforms during k-space sampling. Even with shielded gradients, residual eddy currents and imperfections in gradient amplifier performance can cause the true k-space trajectory to deviate from the ideal trajectory. The k-space determination was used for spiral gradient-echo imaging fo the human brain. While individual calibrations are needed for new pulse sequences, the method of k-space determination can be used for any sequence of preparation pulses and readout gradient waveforms and should prove useful for other trajectories, including the rastered lines of echo-planar imaging.
authors.affiliation: Department of Medicine, University of Alabama at Birmingham, USA.
authors.forename: G F
authors.initials: GF
authors.lastname: Mason
authors.forename: T
authors.initials: T
authors.lastname: Harshbarger
authors.forename: H P
authors.initials: HP
authors.lastname: Hetherington
authors.forename: Y
authors.initials: Y
authors.lastname: Zhang
authors.forename: G M
authors.initials: GM
authors.lastname: Pohost
authors.forename: D B
authors.initials: DB
authors.lastname: Twieg
mesh_terms: D016477:Artifacts; D001921:Brain / Q000033:anatomy & histology*; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D019047:Phantoms, Imaging; D015203:Reproducibility of Results