Multifrequency reconstruction for frequency‐modulated bSSFP. Issue 6 (10th February 2017)

• Record Type: Journal Article
• Authors: Slawig, Anne; Wech, Tobias; Ratz, Valentin; Tran‐Gia, Johannes; Neubauer, Henning; Bley, Thorsten; Köstler, Herbert
• Is Part Of: Magnetic resonance in medicine. Volume 78:Issue 6(2017)
• Page Start: 2226
• Page End: 2235
• Publication Date: 2017-02-10
• Subjects: bSSFP -- banding artifacts -- reconstruction -- frequency modulation; Nuclear magnetic resonance -- Periodicals; Electron paramagnetic resonance -- Periodicals; 616.07548
• DOI: 10.1002/mrm.26630
• Languages: English
• ISSNs: 0740-3194

Abstract

Abstract : 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.