Image Reconstruction for a Rotating Radiofrequency Coil (RRFC) Using Self-Calibrated Sensitivity From Radial Sampling

Area of Science:

• Magnetic Resonance Imaging (MRI)
• High-field MRI (9.4 T)
• Radiofrequency Coil Technology

Background:

• Rotating radiofrequency coils (RRFC) offer potential for advanced MRI applications.
• Accurate calibration of coil sensitivity maps is crucial for image reconstruction.
• Existing methods often rely on simulations or interpolation, which can be complex.

Purpose of the Study:

• To develop a practical MRI imaging scheme for a novel rotating radiofrequency coil (RRFC) at 9.4 T.
• To enable retrospective extraction of time-varying sensitivity maps from k-space data.
• To facilitate accurate image reconstruction without electromagnetic simulations.

Main Methods:

• Integration of a prototype RRFC with an optical sensor for angular position tracking.
• Utilizing radial k-space trajectories with the RRFC.
• Employing an Eigen-decomposition approach to extract location-dependent sensitivity maps.
• Grouping radial spokes based on coil locations for image recovery.

Main Results:

• Successful image reconstruction at 9.4 T using the developed RRFC-MRI scheme.
• Demonstrated retrospective extraction of temporally varying sensitivity maps from k-space.
• Achieved accurate calibration of encoding through controlled RRFC angular velocity.
• Validated approximations to counteract RRFC angular velocity variations.

Conclusions:

• The proposed imaging scheme is practical and enables accurate image reconstruction with RRFCs at 9.4 T.
• The method avoids the need for electromagnetic simulations or numerical interpolation.
• This work supports routine applications of RRFCs and future developments, such as simultaneous multinuclear imaging.