Sensitivity and uniformity improvement of phased array MR images using inductive coupling and RF detuning circuits

Area of Science:

• Magnetic Resonance Imaging (MRI)
• Radiofrequency (RF) Coil Technology
• Biomedical Engineering

Background:

• Phased array RF coils are crucial for MRI sensitivity and uniformity.
• Improving image quality in MRI often requires advanced coil designs.
• Existing coil technologies may face limitations in specific applications.

Purpose of the Study:

• To design an inductively coupled secondary resonator with RF detuning circuits.
• To enhance the sensitivity and uniformity of MR images acquired with a phased array RF coil at 300 MHz.
• To evaluate the performance of the designed secondary resonator using simulations and experiments.

Main Methods:

• Constructed a secondary resonator with detuning circuits to disable it during transmit mode.
• Positioned the secondary resonator opposite a four-channel phased array coil.
• Conducted numerical simulations, phantom experiments, and in vivo mouse imaging.

Main Results:

• Detuning circuits prevented interference, improving magnetic field uniformity (|B1+|) by 57% (reduced SD).
• Enhanced sensitivity and uniformity (|B1-|) in receive mode using the four-channel phased array.
• Phantom studies showed a 20% increase in mean signal intensity and a 50% decrease in SD.

Conclusions:

• The designed secondary resonator with RF detuning circuits effectively improves MR image sensitivity and uniformity.
• This technology is beneficial for acquiring high-quality MR images, as demonstrated in mouse studies.
• The secondary resonator is a valuable addition to phased array RF coil systems for enhanced MRI performance.