title: Accelerated mapping of magnetic susceptibility using 3D planes-on-a-paddlewheel (POP) EPI at ultra-high field strength.
abstract: With the advent of ultra-high field MRI scanners in clinical research, susceptibility based MRI has recently gained increasing interest because of its potential to assess subtle tissue changes underlying neurological pathologies/disorders. Conventional, but rather slow, three-dimensional (3D) spoiled gradient-echo (GRE) sequences are typically employed to assess the susceptibility of tissue. 3D echo-planar imaging (EPI) represents a fast alternative but generally comes with echo-time restrictions, geometrical distortions and signal dropouts that can become severe at ultra-high fields. In this work we assess quantitative susceptibility mapping (QSM) at 7 T using non-Cartesian 3D EPI with a planes-on-a-paddlewheel (POP) trajectory, which is created by rotating a standard EPI readout train around its own phase encoding axis. We show that the threefold accelerated non-Cartesian 3D POP EPI sequence enables very fast, whole brain susceptibility mapping at an isotropic resolution of 1 mm and that the high image quality has sufficient signal-to-noise ratio in the phase data for reliable QSM processing. The susceptibility maps obtained were comparable with regard to QSM values and geometric distortions to those calculated from a conventional 4 min 3D GRE scan using the same QSM processing pipeline. Copyright © 2016 John Wiley & Sons, Ltd.
authors.affiliation: The Centre for Advanced Imaging, The University of Queensland, Brisbane, Queensland, Australia.|Department of Diagnostic and Interventional Radiology, University of Würzburg, Würzburg, Germany.
authors.forename: Daniel
authors.identifier: http://orcid.org/0000-0002-5738-7803
authors.initials: D
authors.lastname: Stäb
authors.affiliation: The Centre for Advanced Imaging, The University of Queensland, Brisbane, Queensland, Australia.
authors.forename: Steffen
authors.initials: S
authors.lastname: Bollmann
authors.affiliation: Department of Neurology, Medical University of Graz, Graz, Austria.
authors.forename: Christian
authors.initials: C
authors.lastname: Langkammer
authors.affiliation: Institute for Mathematics and Scientific Computing, University of Graz, Graz, Austria.
authors.forename: Kristian
authors.initials: K
authors.lastname: Bredies
authors.affiliation: The Centre for Advanced Imaging, The University of Queensland, Brisbane, Queensland, Australia.
authors.forename: Markus
authors.identifier: http://orcid.org/0000-0002-0520-1843
authors.initials: M
authors.lastname: Barth
mesh_terms: D000465:Algorithms; D001921:Brain / Q000033:anatomy & histology* / Q000000981:diagnostic imaging; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods*; D017352:Echo-Planar Imaging / Q000379:methods*; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D021621:Imaging, Three-Dimensional / Q000379:methods*; D060526:Magnetic Fields; D011829:Radiation Dosage; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012815:Signal Processing, Computer-Assisted
keywords: EPI; QSM; brain; non-Cartesian; radial; ultra-high field