title: Rapid measurement and correction of phase errors from B0 eddy currents: impact on image quality for non-Cartesian imaging.
abstract: Non-Cartesian imaging sequences and navigational methods can be more sensitive to scanner imperfections that have little impact on conventional clinical sequences, an issue which has repeatedly complicated the commercialization of these techniques by frustrating transitions to multicenter evaluations. One such imperfection is phase errors caused by resonant frequency shifts from eddy currents induced in the cryostat by time-varying gradients, a phenomenon known as B(0) eddy currents. These phase errors can have a substantial impact on sequences that use ramp sampling, bipolar gradients, and readouts at varying azimuthal angles. We present a method for measuring and correcting phase errors from B(0) eddy currents and examine the results on two different scanner models. This technique yields significant improvements in image quality for high-resolution joint imaging on certain scanners. This result suggests that correcting short-time B(0) eddy currents that do not affect conventional clinical sequences may simplify the adoption of non-Cartesian methods.
authors.affiliation: Department of Medical Physics, University of Wisconsin, Madison, Wisconsin, USA. brodskye@cae.wisc.edu
authors.forename: Ethan K
authors.initials: EK
authors.lastname: Brodsky
authors.forename: Jessica L
authors.initials: JL
authors.lastname: Klaers
authors.forename: Alexey A
authors.initials: AA
authors.lastname: Samsonov
authors.forename: Richard
authors.initials: R
authors.lastname: Kijowski
authors.forename: Walter F
authors.initials: WF
authors.lastname: Block
mesh_terms: D000465:Algorithms; D016477:Artifacts; D007089:Image Enhancement / Q000379:methods*; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity