A truncated twisted solenoid RF phase gradient transmit coil for TRASE MRI

Area of Science:

• Magnetic Resonance Imaging
• Coil Design
• RF Engineering

Background:

• Transmit array spatial encoding (TRASE) enables MRI using cost-effective permanent magnets by employing RF transmit field gradients for k-space encoding.
• Current TRASE implementations often use long twisted solenoid coils, limiting the imaging volume relative to coil length.
• There is a need for more compact coil designs to improve the efficiency and practicality of TRASE MRI systems.

Purpose of the Study:

• To introduce and evaluate a novel truncated coil design for TRASE MRI.
• To increase the usable imaging volume relative to the coil length in TRASE systems.
• To assess the feasibility of using reduced coil lengths without compromising imaging performance.

Main Methods:

• Simulations were performed to determine optimal parameters for a truncated coil design.
• A 200 mm long, 100 mm inner diameter truncated coil pair was constructed.
• The coil pair was tested with an un-shimmed 2.84 MHz Halbach array for TRASE MRI acquisition.

Main Results:

• The truncated coil design successfully created a comparable imaging volume (100 mm length, 80 mm diameter) and quality to untruncated versions.
• Coil length was reduced by up to 50% compared to conventional designs.
• The performance was validated using a permanent magnet Halbach array, demonstrating TRASE feasibility.

Conclusions:

• The truncated coil design offers a significant reduction in coil length for TRASE MRI systems.
• This design enhances the practicality and potential cost-effectiveness of TRASE MRI by improving the coil geometry.
• The findings support the development of more compact and efficient MRI systems utilizing TRASE technology with permanent magnets.