Comparison between fast-interrupted steady-state (FISS) and rapid water-excitation pulses for fat signal suppression in free-running whole-heart MRI at 1.5 T

Yasaman Safarkhanlo; Jérôme Yerly; Mariana B L Falcão; Adèle L C Mackowiak; Davide Piccini; Matthias Stuber; Bernd Jung; Christoph Gräni; Jessica A M Bastiaansen

doi:10.1007/s10334-025-01273-z

Comparison between fast-interrupted steady-state (FISS) and rapid water-excitation pulses for fat signal suppression in free-running whole-heart MRI at 1.5 T

MAGMA. 2025 Jun 23. doi: 10.1007/s10334-025-01273-z. Online ahead of print.

Authors

Yasaman Safarkhanlo^{1

2

3}, Jérôme Yerly^{4

5}, Mariana B L Falcão⁴, Adèle L C Mackowiak^{2

4

6}, Davide Piccini^{4

7}, Matthias Stuber^{4

5}, Bernd Jung^{2

6}, Christoph Gräni^{1

2}, Jessica A M Bastiaansen^{8

9}

Affiliations

¹ Department of Cardiology, University Hospital Bern, Bern, Switzerland.
² Translation Imaging Center (TIC), Swiss Institute for Translational and Entrepreneurial Medicine, Bern, Switzerland.
³ Graduate School for Cellular and Biomedical Sciences (GCB), University of Bern, Bern, Switzerland.
⁴ Department of Diagnostic and Interventional Radiology, Lausanne University Hospital (CHUV), University of Lausanne (UNIL), Lausanne, Switzerland.
⁵ Center for Biomedical Imaging, Lausanne, Switzerland.
⁶ Department of Diagnostic, Interventional and Pediatric Radiology (DIPR), Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland.
⁷ Advanced Clinical Imaging Technology, Siemens Healthineers International AG, Lausanne, Switzerland.
⁸ Translation Imaging Center (TIC), Swiss Institute for Translational and Entrepreneurial Medicine, Bern, Switzerland. jbastiaansen.mri@gmail.com.
⁹ Department of Diagnostic, Interventional and Pediatric Radiology (DIPR), Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland. jbastiaansen.mri@gmail.com.

PMID: 40549260
DOI: 10.1007/s10334-025-01273-z

Abstract

Background: Free-running whole-heart MRI using balanced steady-state free precession (bSSFP) sequences offer high SNR and myocardial tissue contrast. However, an inadequate fat signal suppression may introduce artifacts and is particularly challenging with non-Cartesian readouts. The aim of this study was to evaluate different fat-signal suppression methods for whole-heart free-running MRI at 1.5 T using numerical simulations, phantom, and cardiac MRI experiments without the use of contrast agents.

Methods: Binomial off-resonant rectangular (BORR), lipid insensitive binomial off-resonant RF excitation (LIBRE), and lipid insensitive binomial off-resonant (LIBOR) pulses were implemented within a 3D radial bSSFP sequence. Their pulse parameters were optimized for fat signal suppression at 1.5 T using simulations and phantom experiments. Optimized protocols, along with a free-running fast interrupted steady-state (FISS) and non-fat suppressed bSSFP sequence, were used to acquire phantom and cardiac data in five volunteers. SAR values were recorded. The SNR and CNR_Water-Fat were measured in phantom data, while SNR and CNR_{Blood-Myocardium} were quantified in volunteers using reconstruction without motion correction. Motion-resolved reconstructions were used for qualitative assessments. Statistical differences were analyzed using one-way ANOVA.

Results: LIBOR had the highest CNR_Water-Fat (276.8 ± 2.5) in phantoms, followed by LIBRE (268.1 ± 2.6), BORR (249.9 ± 2.2), and FISS (212.7 ± 2.7), though these differences were not statistically significant (p > 0.05). In volunteers, BORR had the highest SNR in the ventricular blood pool (17.0 ± 1.5), and LIBRE had the highest CNR_Blood-Fat (29.4 ± 9.3). FISS had the highest CNR_{Blood-Myocardium} (29.0 ± 8.9), but the differences were not significant (p > 0.05). Motion-resolved cardiac imaging showed comparable quality across all fat-suppressed sequences, with no significant streaking artifacts observed. Free-running bSSFP with LIBOR required the lowest SAR, up to a sixfold decrease compared with FISS.

Conclusion: The tested sequences performed similarly in SNR and CNR but LIBOR offered the lowest SAR, making it a promising candidate for applications where RF energy deposition is a concern.

Keywords: 1.5 T; 5D whole-heart free-running CMR; FISS; Fat suppression; LIBRE; Off-resonance; bSSFP.

Grants and funding

PCEFP2_194296/Schweizerischer Nationalfonds zur Förderung der Wissenschaftlichen Forschung