External waveguide magnetic resonance imaging for lower limbs at 3 T.

Area of Science:

• Medical Imaging
• Magnetic Resonance Imaging
• Biophysics

Background:

• Conventional MRI systems face limitations in achieving large field-of-view imaging, particularly for anatomical regions like the lower limbs.
• External radiofrequency (RF) components can enhance MRI capabilities but require careful integration to maintain image quality and safety.

Purpose of the Study:

• To introduce and evaluate a novel traveling-wave MRI method for acquiring images of human lower limbs at 3 Tesla (3T).
• To demonstrate the feasibility of using an external waveguide and RF surface coil for enhanced MRI signal reception.

Main Methods:

• A parallel-plate waveguide and an RF surface coil were employed for signal reception, positioned outside the MRI scanner.
• A standard whole-body birdcage coil served as the transmitter.
• Numerical simulations were conducted to analyze the electromagnetic field distribution.
• Phantom studies and imaging of a healthy volunteer's lower limb were performed.

Main Results:

• Numerical simulations validated the electromagnetic field generated by the external components.
• Phantom imaging demonstrated a measurable signal-to-noise ratio, confirming simulation accuracy.
• High-quality lower limb images were successfully acquired from a healthy volunteer.
• The technique required no physical modifications to the existing MRI scanner.

Conclusions:

• Traveling-wave MRI with an external waveguide and RF coil is a practical approach for high-quality imaging at 3T.
• This method is particularly advantageous for imaging lower limbs, enabling a larger field of view.
• The technique offers a simplified and potentially more cost-effective solution for specific MRI applications.