A 128-channel receive array with enhanced signal-to-noise ratio performance for 10.5T brain imaging

Area of Science:

• Magnetic Resonance Imaging (MRI)
• Neuroimaging
• Radiofrequency Coil Engineering

Background:

• High-field MRI (≥7 Tesla) offers potential for enhanced brain imaging.
• Developing advanced radiofrequency (RF) coils is crucial for maximizing signal-to-noise ratio (SNR) at ultra-high fields.
• Optimizing coil design is essential to mitigate challenges like radiofrequency (RF) field inhomogeneity and losses.

Purpose of the Study:

• To develop and characterize a novel 128-channel head array for 10.5 Tesla (T) brain MRI.
• To evaluate the signal-to-noise ratio (SNR) performance relative to ultimate intrinsic SNR (uiSNR) and lower field strengths.
• To demonstrate the capability for high-quality human brain anatomical and functional imaging at 10.5 T using the developed array.

Main Methods:

• A 128-channel array was constructed, comprising a 16-channel transmit/receive (Tx/Rx) array with a 112-channel receive-only (Rx) insert.
• Interactions between transmit and receive elements were minimized using coaxial cable traps and strategic preamplifier placement.
• Electromagnetic simulations and experimental measurements were used to characterize coil performance.

Main Results:

• The 128-channel array achieved 77% of the central uiSNR, approaching a plateau around 80% with increasing channel count.
• Significantly higher 1/g-factor values were observed across the whole brain compared to 7 T systems.
• High-resolution anatomical and functional brain images were successfully acquired, demonstrating excellent SNR and parallel imaging performance.

Conclusions:

• The 128-channel array at 10.5 T provides substantial SNR gains, contrary to expectations for fields ≤7 T.
• The achieved SNR gains at 10.5 T relative to 7 T scale approximately linearly for the periphery and quadratically for the center.
• The developed coil technology facilitates high-quality neuroimaging at ultra-high fields, pushing the boundaries of anatomical and functional brain exploration.