title: Suppression of MRI truncation artifacts using total variation constrained data extrapolation.
abstract: The finite sampling of k-space in MRI causes spurious image artifacts, known as Gibbs ringing, which result from signal truncation at the border of k-space. The effect is especially visible for acquisitions at low resolution and commonly reduced by filtering at the expense of image blurring. The present work demonstrates that the simple assumption of a piecewise-constant object can be exploited to extrapolate the data in k-space beyond the measured part. The method allows for a significant reduction of truncation artifacts without compromising resolution. The assumption translates into a total variation minimization problem, which can be solved with a nonlinear optimization algorithm. In the presence of substantial noise, a modified approach offers edge-preserving denoising by allowing for slight deviations from the measured data in addition to supplementing data. The effectiveness of these methods is demonstrated with simulations as well as experimental data for a phantom and human brain in vivo.
authors.affiliation: Biomedizinische NMR Forschungs GmbH, Max-Planck-Institut für biophysikalische Chemie, 37070 Göttingen, Germany. tblock@gwdg.de
authors.forename: Kai Tobias
authors.initials: KT
authors.lastname: Block
authors.forename: Martin
authors.initials: M
authors.lastname: Uecker
authors.forename: Jens
authors.initials: J
authors.lastname: Frahm
references.citation: IEEE Trans Med Imaging. 2001 Nov;20(11):1178-83
references.pmid: 11700743
references.citation: IEEE Trans Image Process. 1995;4(7):932-46
references.pmid: 18290044
references.citation: Magn Reson Med. 2005 Dec;54(6):1490-502
references.pmid: 16254953
references.citation: Magn Reson Imaging. 1990;8(2):173-83
references.pmid: 2338898
references.citation: IEEE Trans Med Imaging. 2002 Apr;21(4):305-19
references.pmid: 12022619
references.citation: Magn Reson Med. 2007 Jun;57(6):1086-98
references.pmid: 17534903
references.citation: J Magn Reson Imaging. 1991 Nov-Dec;1(6):721-4
references.pmid: 1823178
references.citation: J Magn Reson Imaging. 1991 May-Jun;1(3):307-17
references.pmid: 1802144
references.citation: Magn Reson Med. 1991 Jan;17(1):108-18
references.pmid: 2067388