In vivo sensitivity estimation and imaging acceleration with rotating RF coil arrays at 7 Tesla

Area of Science:

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

Background:

• Ultra-high field MRI (7 Tesla) offers enhanced signal-to-noise ratio but faces challenges with radiofrequency (RF) coil sensitivity.
• Rotating RF coil arrays (RRFCA) show potential for accelerated MRI acquisition and uniform image reconstruction.
• Standard rotating-SENSE algorithms struggle with distinct in vivo sensitivity profiles at different angular positions in 7T MRI.

Purpose of the Study:

• To develop and validate a novel sensitivity estimation method for RRFCA at 7T.
• To enable accurate image reconstruction and accelerated acquisition using RRFCA at ultra-high fields.
• To improve image quality and scan time efficiency in 7T MRI.

Main Methods:

• Developed a rotation-dependent sensitivity estimation method using a library database and registration techniques.
• Validated the method with human brain imaging at 7 Tesla.
• Employed the estimated sensitivity maps with the rotating-SENSE algorithm for accelerated image reconstruction.

Main Results:

• The proposed method accurately estimated both magnitude and phase of coil sensitivity at arbitrary angular positions.
• RRFCA, utilizing the new estimation method, achieved accelerated acquisition and uniform image reconstruction.
• Compared to stationary coils, RRFCA reconstructed images with superior quality at high acceleration factors.

Conclusions:

• The novel sensitivity estimation method overcomes limitations of standard rotating-SENSE at 7T.
• This approach facilitates the use of RRFCA for significantly faster and higher-quality ultra-high field MRI.
• The developed algorithm is expected to be highly valuable for advanced 7T MRI applications.