Frequency-modulated bSSFP for phase-sensitive separation of water and fat

• Published in: Magnetic resonance imaging 2018-11, Vol.53, p.82-88
• Main Authors: Slawig, Anne, Wech, Tobias, Ratz, Valentin, Neubauer, Henning, Bley, Thorsten, Köstler, Herbert
• Format: Article
• Language: English
• Subjects: Acquisition methods; bSSFP; Frequency-modulation; Post-acquisition processing; Water fat imaging
• ISSN: 0730-725X; 1873-5894
• DOI: 10.1016/j.mri.2018.06.005

Our study proposes the use of a frequency-modulated acquisition which suppresses banding artefacts in combination with a phase-sensitive water-fat separation algorithm. The performance of the phase-sensitive separation for standard bSSFP, complex sum combination thereof, and frequency-modulated bSSFP were compared in in vivo measurements of the upper and lower legs at 1.5 and 3 T. It is shown, that the standard acquisition suffered from banding artefacts and major swaps between tissues. The dual-acquisition bSSFP could alleviate banding artefacts and only minor swaps occurred, but it comes at the expense of a doubled acquisition. In the frequency-modulated acquisitions all banding artefacts and the associated phase jumps were eliminated and no swaps between tissues occurred. It therefore provides a means to robustly separate water and fat, in one single radial bSSFP scan, using the phase-sensitive approach, even in the presence of high field inhomogeneities.