Enhanced spectral shaping in steady-state free precession imaging

Area of Science:

• Magnetic Resonance Imaging (MRI)
• Biomedical Engineering
• Medical Physics

Background:

• Balanced steady-state free precession (SSFP) imaging suffers from off-resonance artifacts and bright fat signals.
• Existing methods for artifact reduction, such as complex-sum SSFP and sum-of-squares SSFP, have limitations in balancing banding reduction and SNR efficiency.
• Current fat suppression techniques can lead to imperfect suppression due to the shape of their stop-bands.

Purpose of the Study:

• To introduce a novel weighted-combination SSFP (WC-SSFP) method for improved SSFP imaging.
• To address the challenges of banding artifacts and fat signal suppression in SSFP sequences.
• To develop a flexible method that allows for adjustable banding reduction and fat suppression.

Main Methods:

• A new multiple-acquisition SSFP combination technique, WC-SSFP, was developed.
• The method utilizes multiple datasets with varying RF phase increments.
• WC-SSFP was evaluated for its ability to preserve SSFP contrast, reduce banding, and separate fat and water signals.

Main Results:

• WC-SSFP effectively reduces banding artifacts while maintaining high SNR efficiency, comparable to sum-of-squares SSFP.
• The method significantly improves fat suppression by enhancing the stop-band performance without compromising pass-band characteristics.
• WC-SSFP demonstrates robustness in the presence of resonant frequency variations, preventing fat signal interference.

Conclusions:

• WC-SSFP offers a superior solution for mitigating banding artifacts and suppressing fat signals in SSFP MRI.
• The technique provides robust performance and preserves image contrast, enhancing diagnostic utility.
• WC-SSFP introduces a tunable parameter for application-specific optimization of banding reduction and fat suppression.