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A Modified Balanced Steady State Free Precession Sequence for Overhauser Magnetic Resonance Imaging.
Kai Buckenmaier1, Friedemann Bullinger1, Georgiy Alekseevich Solomakha1
1High-Field Magnetic Resonance Center, Max Planck Institute for Biological Cybernetics, Tübingen, Germany.
Magnetic Resonance in Medicine
|June 8, 2026
Summary
A new modified balanced steady-state free precession (bSSFP) sequence, bSSFP180, effectively suppresses banding artifacts in Overhauser dynamic nuclear polarization (ODNP)-enhanced ultralow-field magnetic resonance imaging (ULF MRI). This advancement enables artifact-free imaging in challenging low-field environments.
Area of Science:
- Magnetic Resonance Imaging
- Biomedical Engineering
- Physics
Background:
- Low- and ultralow-field magnetic resonance imaging (ULF MRI) suffer from low signal-to-noise ratio (SNR).
- Overhauser dynamic nuclear polarization (ODNP) enhances signal but requires high radiofrequency (RF) power and efficient pulse sequences.
- Conventional balanced steady-state free precession (bSSFP) sequences are prone to banding artifacts due to field inhomogeneities.
Purpose of the Study:
- To develop and validate a modified bSSFP sequence for ODNP-enhanced ULF MRI.
- To mitigate banding artifacts inherent in conventional bSSFP sequences.
- To improve the reliability of ULF MRI in low-field settings.
Main Methods:
- Development of a modified bSSFP sequence (bSSFP180) with interleaved polarization and acquisition.
- Comparison of the modified bSSFP180 sequence against the unmodified sequence.
- Experimental validation of the sequence's performance under inhomogeneous field conditions.
Main Results:
- The bSSFP180 sequence effectively suppresses banding artifacts.
- The sequence demonstrates robust performance even with B0 inhomogeneities.
- Experimental ULF MRI results confirmed artifact-free imaging with bSSFP180.
Conclusions:
- The bSSFP180 sequence represents a significant advancement for ODNP-enhanced ULF MRI.
- This technique enhances the practical and reliable use of ULF MRI in biomedical applications.
- It is particularly beneficial for cost-efficient, permanent magnet systems prone to field instability.
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