title: Multifrequency reconstruction for frequency-modulated bSSFP.
abstract: OBJECTIVE
  Banding artifacts in images acquired by balanced steady-state free precession (bSSFP) remain a challenge in MRI as they considerably reduce image quality, and diagnostic value deteriorates accordingly. As the steady-state tolerates small shifts in frequency, it is possible to acquire frequency-modulated bSSFP. Unfortunately, standard reconstructions of such measurements suffer from signal loss. Our study proposes a multifrequency reconstruction and demonstrates its capability of suppressing banding artifacts while retaining the high signal level of standard bSSFP.
  
  
  METHODS
  Numerical simulations in vitro and in vivo measurements were performed using both standard bSSFP and frequency-modulated bSSFP. The modulated data were reconstructed using a multifrequency approach consisting of three steps: phase correction, multiple reconstructions for different assumed frequencies, and maximum intensity projection.
  
  
  RESULTS
  Although standard bSSFP measurements showed banding artifacts that compromised the image quality, standard reconstructions of frequency-modulated acquisitions suffered from signal loss. In contrast, images reconstructed from frequency-modulated data using the proposed multifrequency reconstruction showed no visual bandings and featured a higher signal-to-noise ratio (SNR). The SNR gain for phantom and in vivo measurements ranged from 1.23 to 1.49.
  
  
  CONCLUSIONS
  The presented multifrequency reconstruction for frequency-modulated bSSFP provides images showing no bandings and featuring high SNR in short scan times. Magn Reson Med 78:2226-2235, 2017. © 2017 International Society for Magnetic Resonance in Medicine.
authors.affiliation: Department of Diagnostic and Interventional Radiology, University of Würzburg, Würzburg, Germany.
authors.forename: Anne
authors.initials: A
authors.lastname: Slawig
authors.affiliation: Department of Diagnostic and Interventional Radiology, University of Würzburg, Würzburg, Germany.
authors.forename: Tobias
authors.initials: T
authors.lastname: Wech
authors.affiliation: Department of Diagnostic and Interventional Radiology, University of Würzburg, Würzburg, Germany.
authors.forename: Valentin
authors.initials: V
authors.lastname: Ratz
authors.affiliation: Department of Diagnostic and Interventional Radiology, University of Würzburg, Würzburg, Germany.|Department of Nuclear Medicine, University of Würzburg, Würzburg, Germany.
authors.forename: Johannes
authors.initials: J
authors.lastname: Tran-Gia
authors.affiliation: Department of Diagnostic and Interventional Radiology, University of Würzburg, Würzburg, Germany.
authors.forename: Henning
authors.initials: H
authors.lastname: Neubauer
authors.affiliation: Department of Diagnostic and Interventional Radiology, University of Würzburg, Würzburg, Germany.
authors.forename: Thorsten
authors.initials: T
authors.lastname: Bley
authors.affiliation: Department of Diagnostic and Interventional Radiology, University of Würzburg, Würzburg, Germany.
authors.forename: Herbert
authors.initials: H
authors.lastname: Köstler
mesh_terms: D000465:Algorithms; D016477:Artifacts; D001921:Brain / Q000000981:diagnostic imaging*; D003198:Computer Simulation; D007758:Ear, Inner / Q000000981:diagnostic imaging*; D017352:Echo-Planar Imaging; D005583:Fourier Analysis; D064368:Healthy Volunteers; D006801:Humans; D007089:Image Enhancement; D007090:Image Interpretation, Computer-Assisted; D007091:Image Processing, Computer-Assisted; D007866:Leg / Q000000981:diagnostic imaging*; D016014:Linear Models; D008279:Magnetic Resonance Imaging; D016011:Normal Distribution; D019047:Phantoms, Imaging; D015203:Reproducibility of Results; D012815:Signal Processing, Computer-Assisted; D059629:Signal-To-Noise Ratio
keywords: bSSFP; banding artifacts; frequency modulation; reconstruction