Four-row MRI receive array with remote circuitry for improved parallel imaging in radiation therapy systems.

Area of Science:

• Medical Imaging
• Magnetic Resonance Imaging
• Radiation Oncology

Background:

• Previous MR guided radiation therapy (MRgRT) coil arrays were limited to 1-2 rows due to circuitry placement constraints.
• Limited coil rows restrict parallel imaging undersampling in the head-foot direction, impacting MRgRT performance.
• A three-row array with remote circuitry previously improved parallel imaging while maintaining SNR and radiolucency.

Purpose of the Study:

• To evaluate a prototype four-row radiofrequency coil array for MRgRT.
• To determine if a four-row design offers further parallel imaging advantages over existing MRgRT coil configurations.
• To assess the feasibility of advanced coil designs for enhanced MRgRT capabilities.

Main Methods:

• Developed remote circuits to position radio-opaque components outside the radiation beam path.
• Engineered circuits included phase shifters, tuning, matching, detuning, and preamplifier decoupling.
• Tested coil performance using an abdominal phantom and a 16-channel four-row array.

Main Results:

• The four-row array achieved SNR comparable to two- and three-row designs.
• Enabled 3x head-foot acceleration (min reciprocal g-factor = 0.74).
• Supported 2x3 multi-directional acceleration (min reciprocal g-factor = 0.72), surpassing previous designs.

Conclusions:

• Demonstrated the technical feasibility of four-row MRgRT coil arrays.
• These designs can significantly benefit MRgRT applications demanding high SNR and temporal resolution.
• The advanced coil configuration offers improved parallel imaging capabilities for radiation therapy.