Brain imaging with improved acceleration and SNR at 7 Tesla obtained with 64-channel receive array

Magn Reson Med. 2019 Jul;82(1):495-509. doi: 10.1002/mrm.27695. Epub 2019 Feb 25.


Purpose: Despite the clear synergy between high channel counts in a receive array and magnetic fields ≥ 7 Tesla, to date such systems have been restricted to a maximum of 32 channels. Here, we examine SNR gains at 7 Tesla in unaccelerated and accelerated images with a 64-receive channel (64Rx) RF coil.

Methods: A 64Rx coil was built using circular loops tiled in 2 separable sections of a close-fitting form; custom designed preamplifier boards were integrated into each coil element. A 16-channel transmitter arranged in 2 rows along the z-axis was employed. The performance of the 64Rx array was experimentally compared to that of an industry-standard 32-channel receive (32Rx) array for SNR in unaccelerated images and for noise amplification under parallel imaging.

Results: SNR gains were observed in the periphery but not in the center of the brain in unaccelerated imaging compared to the 32Rx coil. With either 1D or 2D undersampling of k-space, or with slice acceleration together with 1D undersampling of k-space, significant reductions in g-factor noise were observed throughout the brain, yielding effective gains in SNR in the entire brain compared to the 32Rx coil. Task-based FMRI data with 12-fold 2D (slice and phase-encode) acceleration yielded excellent quality functional maps with the 64Rx coil but was significantly beyond the capabilities of the 32Rx coil.

Conclusion: The results confirm the expectations from modeling studies and demonstrate that whole-brain studies with up to 16-fold, 2D acceleration would be feasible with the 64Rx coil.

Keywords: RF coils; functional imaging; multiband; neuroimaging; parallel imaging; simultaneous multislice.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Adult
  • Brain / diagnostic imaging*
  • Equipment Design
  • Female
  • Humans
  • Image Processing, Computer-Assisted / instrumentation*
  • Image Processing, Computer-Assisted / methods*
  • Magnetic Resonance Imaging / methods*
  • Male
  • Neuroimaging / methods*
  • Phantoms, Imaging
  • Signal-To-Noise Ratio
  • Young Adult