96-Channel receive-only head coil for 3 Tesla: design optimization and evaluation

Area of Science:

• Magnetic Resonance Imaging (MRI)
• Medical Device Engineering
• Neuroimaging

Background:

• Highly parallel array coils are crucial for advanced MRI techniques like accelerated imaging.
• Optimizing coil design is essential to mitigate signal-to-noise ratio (SNR) loss due to coil loading and element coupling.
• Previous head coils, such as 12- and 32-channel arrays, have limitations in achieving high acceleration rates with adequate image quality.

Purpose of the Study:

• To develop and evaluate a 96-channel receive-only phased-array head coil for 3T MRI.
• To investigate the benefits and challenges of highly parallel coils for head imaging.
• To assess SNR and g-factor performance in accelerated imaging compared to existing head coils.

Main Methods:

• Construction of a 96-channel phased-array head coil on a helmet-shaped former.
• Evaluation of coil element and matching circuitry designs, focusing on SNR loss factors.
• Quantitative assessment of SNR and g-factor using phantom and human brain imaging.
• Comparison with a 32-channel and a commercial 12-channel head coil.

Main Results:

• The 96-channel coil demonstrated substantial SNR gains in the distal cortex compared to 12- and 32-channel coils.
• Central SNR was comparable to the 32-channel coil using optimal combination, but 20% lower with root-sum-of-squares.
• A significant reduction in the maximum g-factor was observed; for acceleration rate 4, the 96-channel coil's max g-factor was 65% of the 32-channel coil's value.
• The coil enabled highly accelerated brain imaging with demonstrated performance.

Conclusions:

• The developed 96-channel head coil offers significant advantages for accelerated neuroimaging.
• It provides improved SNR in critical brain regions and reduced noise amplification, facilitating higher acceleration factors.
• This technology represents a promising advancement for faster and more detailed brain MRI scans.