Accelerated mapping of magnetic susceptibility using 3D planes‐on‐a‐paddlewheel (POP) EPI at ultra‐high field strength. (20th October 2016)

• Record Type: Journal Article
• Authors: Stäb, Daniel; Bollmann, Steffen; Langkammer, Christian; Bredies, Kristian; Barth, Markus
• Other Names: Liu Chunlei guestEditor.; Bowtell Richard guestEditor.; Schenck John guestEditor.
• Is Part Of: NMR in biomedicine. Volume 30:Number 4(2017:Apr.)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2016-10-20
• Subjects: brain -- EPI -- non‐Cartesian -- ultra‐high field -- radial -- QSM; Nuclear magnetic resonance -- Periodicals; Magnetic Resonance Spectroscopy -- Periodicals; 574
• DOI: 10.1002/nbm.3620
• Languages: English
• ISSNs: 0952-3480

Abstract

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. Abstract : Ultra‐high field whole brain susceptibility mapping at an isotropic resolution of 1 mm was performed within 39 s using a 3D planes‐on‐a‐paddlewheel (POP) EPI sequence. The non‐Cartesian readout scheme is created by rotating a standard EPI readout train around its own phase encoding axis, and provides higher flexibility for echo‐time minimization than conventional 3D EPI. Morphologic images, susceptibility maps and values obtained were comparable to those acquired with a conventional 4 min 3D GRE scan.