Wideband receive-coil array design using high-impedance amplifiers for broadband decoupling.

Area of Science:

• Magnetic Resonance Imaging
• Coil Engineering
• Nuclear Magnetic Resonance Spectroscopy

Background:

• Multinuclear MRI/S is gaining traction, but current coil designs are complex, requiring multiple preamplifiers and decoupling circuits for different nuclei.
• Existing methods for multinuclear receive array coils involve nesting single-tuned coils or using complex switching elements, leading to increased complexity with more channels or nuclei.

Purpose of the Study:

• To introduce a novel coil decoupling mechanism for multinuclear array coils that simplifies hardware requirements.
• To enable broadband decoupling using a single set of preamplifiers, reducing complexity in multinuclear MRI/S systems.

Main Methods:

• A high-input impedance preamplifier was employed to achieve broadband decoupling, replacing conventional isolation preamplifiers.
• A multi-tuned matching network (inductor-capacitor-capacitor) and a wire-wound transformer were used to connect the surface coil to the high-impedance preamplifier.
• The proposed configuration was bench and scanner tested against conventional preamplifier decoupling methods.

Main Results:

• The novel approach achieved over 15dB decoupling across a 25MHz bandwidth, covering 23Na and 2H Larmor frequencies at 4.7T.
• The multi-tuned prototype demonstrated 61% (2H) and 76% (23Na) of imaging SNR compared to conventional methods.
• In higher loading conditions, the prototype maintained 76% (2H) and 89% (23Na) of SNR relative to conventional configurations.

Conclusions:

• This work presents a simplified method for constructing high element-count multinuclear array coils.
• The proposed technique enables broadband decoupling with a single layer of array coil and preamplifiers.
• The approach facilitates accelerated imaging and improved SNR in multinuclear MRI/S applications.