Magnetic resonance in medicine · 2026
A Modified Balanced Steady State Free Precession Sequence for Overhauser Magnetic Resonance Imaging.
СтатьяНазвание и аннотация: Перевод в очереди
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Buckenmaier Kai, Bullinger Friedemann, Solomakha Georgiy Alekseevich, Schneider Marcel, Engelmann Jörn, Pohlmann Philipp, Povolni Pavel, Kuebler Laura, Martins André Ferreira, Scheffler Klaus
Аннотация
PURPOSE: Low- and ultralow-field magnetic resonance imaging (ULF MRI) have inherently low signal-to-noise ratio (SNR) by design. Overhauser dynamic nuclear polarization (ODNP) stands out as an effective solution for continuous signal enhancement. To accelerate imaging and reduce radiofrequency (RF) power deposition-which is critical due to the high-frequency RF fields required for ODNP-efficient pulse sequences are essential. For instance, a balanced steady-state free precession (bSSFP) sequence offers high signal efficiency. However, conventional bSSFP sequences are susceptible to B0 inhomogeneities and temporal field drifts, which can lead to banding artifacts.
METHODS: In this work, we mitigated the limitations of banding artifacts by developing a modified bSSFP sequence (bSSFP180) that allows interleaved polarization and acquisition, thereby tailoring it for ODNP-enhanced ULF MRI. The unmodified and modified sequences are compared in an imaging experiment.
RESULTS: The proposed sequence effectively suppresses banding artifacts and demonstrates robust performance under inhomogeneous field conditions. Experimental MRI results demonstrated that bSSFP 180 achieves banding artifact-free performance.
CONCLUSION: The banding artifact-free bSSFP180 images represent a significant advancement toward the practical and reliable use of ODNP-enhanced imaging in future biomedical applications. This is particularly relevant for MRI experiments that employ lightweight, cost-efficient, permanent magnet systems in low-field environments, which often face challenges related to field instability and inhomogeneity.
METHODS: In this work, we mitigated the limitations of banding artifacts by developing a modified bSSFP sequence (bSSFP180) that allows interleaved polarization and acquisition, thereby tailoring it for ODNP-enhanced ULF MRI. The unmodified and modified sequences are compared in an imaging experiment.
RESULTS: The proposed sequence effectively suppresses banding artifacts and demonstrates robust performance under inhomogeneous field conditions. Experimental MRI results demonstrated that bSSFP 180 achieves banding artifact-free performance.
CONCLUSION: The banding artifact-free bSSFP180 images represent a significant advancement toward the practical and reliable use of ODNP-enhanced imaging in future biomedical applications. This is particularly relevant for MRI experiments that employ lightweight, cost-efficient, permanent magnet systems in low-field environments, which often face challenges related to field instability and inhomogeneity.