Multifrequency reconstruction for frequency-modulated bSSFP.

Autor: Slawig A; Department of Diagnostic and Interventional Radiology, University of Würzburg, Würzburg, Germany., Wech T; Department of Diagnostic and Interventional Radiology, University of Würzburg, Würzburg, Germany., Ratz V; Department of Diagnostic and Interventional Radiology, University of Würzburg, Würzburg, Germany., Tran-Gia J; Department of Diagnostic and Interventional Radiology, University of Würzburg, Würzburg, Germany.; Department of Nuclear Medicine, University of Würzburg, Würzburg, Germany., Neubauer H; Department of Diagnostic and Interventional Radiology, University of Würzburg, Würzburg, Germany., Bley T; Department of Diagnostic and Interventional Radiology, University of Würzburg, Würzburg, Germany., Köstler H; Department of Diagnostic and Interventional Radiology, University of Würzburg, Würzburg, Germany.
Jazyk: angličtina
Zdroj: Magnetic resonance in medicine [Magn Reson Med] 2017 Dec; Vol. 78 (6), pp. 2226-2235. Date of Electronic Publication: 2017 Feb 10.
DOI: 10.1002/mrm.26630
Abstrakt: Purpose: 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.
(© 2017 International Society for Magnetic Resonance in Medicine.)
Databáze: MEDLINE
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