title: Center-out echo-planar spectroscopic imaging with correction of gradient-echo phase and time shifts.
abstract: A procedure to prevent the formation of image and spectral Nyquist ghosts in echo-planar spectroscopic imaging is introduced. It is based on a novel Cartesian center-out echo-planar spectroscopic imaging trajectory, referred to as EPSICO, and combined with a correction of the gradient-echo phase and time shifts. Processing of homogenous sets of forward and reflected echoes is no longer necessary, resulting in an optimized spectral width. The proposed center-out trajectory passively prevents the formation of Nyquist ghosts by privileging the acquisition of the center k-space line with forward echoes at the beginning of an echo-planar spectroscopic imaging dwell time and by ensuring that all k-space lines and their respective complex conjugates are acquired at equal time intervals. With the proposed procedure, concentrations of N-acetyl aspartate, creatine, choline, glutamate, and myo-inositol were reliably determined in human white matter at 3 T.
authors: Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany.
authors: Christian
authors: C
authors: Labadie
authors: Stefan
authors: S
authors: Hetzer
authors: Jessica
authors: J
authors: Schulz
authors: Toralf
authors: T
authors: Mildner
authors: Monique
authors: M
authors: Aubert-Frécon
authors: Harald E
authors: HE
authors: Möller
mesh_terms: D000465:Algorithms; D016477:Artifacts; D001923:Brain Chemistry; D017352:Echo-Planar Imaging / Q000379:methods*; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D009413:Nerve Fibers, Myelinated / Q000737:chemistry*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity