A 128-channel receive array with enhanced SNR performance for 10.5 tesla brain imaging

Area of Science:

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

Background:

• Ultra-high field (UHF) MRI, particularly at 10.5 tesla (T), offers potential for enhanced brain imaging.
• Developing advanced radiofrequency (RF) coils is crucial for optimizing performance at these higher fields.

Purpose of the Study:

• To develop and characterize a 128-channel head array for brain imaging at 10.5 T.
• To evaluate the potential of brain imaging at magnetic fields exceeding 10 T.

Main Methods:

• A 128-channel coil comprising a 16-channel transmit/receive array and a 112-channel receive-only insert was designed.
• Interactions were mitigated using coaxial cable traps, and preamplifier boards were strategically placed outside the transmit field or miniaturized.

Main Results:

• The 128-channel array achieved 77% of ultimate intrinsic signal-to-noise ratio (SNR) in the brain's center.
• Transmit field maps validated the design, leading to FDA approval for human imaging.
• Successful acquisition of anatomical and functional MRI data in human volunteers was demonstrated.

Conclusions:

• Contrary to expectations for fields ≤7 T, higher channel counts at 10.5 T provided central SNR gains, reaching approximately 80% of ultimate SNR.
• SNR gains at 10.5 T relative to 7 T showed a transition from linear to quadratic dependence on the B0 field for the periphery and center, respectively.