Fat/water separation in single acquisition steady-state free precession using multiple echo radial trajectories

Area of Science:

• Medical Imaging
• Magnetic Resonance Imaging (MRI)
• Biophysics

Background:

• Conventional fat/water separation in fast low-angle shot (FLASH) imaging often requires magnetization preparation or multiple acquisitions.
• Exploiting phase differences between fat and water at specific echo times is a key strategy for improved separation.
• Minimizing the repetition time (TR) enhances robustness against B0 inhomogeneity, crucial for high-quality imaging.

Purpose of the Study:

• To develop a novel method for fat and water separation in fully refocused SSFP imaging.
• To achieve fat/water separation in a single acquisition, reducing scan time and complexity.
• To improve robustness to B0 inhomogeneity and enhance contrast between fat and water tissues.

Main Methods:

• Utilized phase detection exploiting the inherent phase difference between fat and water.
• Implemented a 3D projection acquisition collecting two half echoes per excitation.
• Developed a linear combination technique to merge half echoes for single-pass k-space data acquisition.

Main Results:

• Successfully separated fat and water in a single acquisition using the novel linear combination method.
• Achieved superior contrast between fat and water voxels compared to previous methods.
• Demonstrated improved robustness to B0 inhomogeneity in high-resolution angiography and musculoskeletal imaging.
• Reduced scan time by 50% compared to the prior two-pass k-space acquisition method.

Conclusions:

• The presented phase detection method enables efficient fat/water separation in fully refocused SSFP imaging.
• Single-acquisition separation significantly reduces scan time and improves robustness, making it clinically advantageous.
• This technique offers superior fat/water contrast, beneficial for detailed anatomical and pathological assessments.