A combined 32-channel receive-loops/8-channel transmit-dipoles coil array for whole-brain MR imaging at 7T

TY - JOUR

T1 - A combined 32-channel receive-loops/8-channel transmit-dipoles coil array for whole-brain MR imaging at 7T

AU - Clément, Jérémie

AU - Gruetter, Rolf

AU - Ipek, Özlem

PY - 2019/9/1

Y1 - 2019/9/1

N2 - Purpose : Multichannel receive arrays provide high SNR and parallel-imaging capabilities, while transmit-only dipole arrays have been shown to achieve a large coverage of the whole-brain including the cerebellum. The aim of this study was to develop and characterize the performances of a 32-channel receive-only loop array combined with an 8-channel dipole coil array at 7T for the first time. Methods : The 8Tx-dipoles/32Rx-loops coil array was characterized by the SNR, g-factors, noise correlation matrix, accelerated image quality, and B + 1 maps, and compared with a commercial 1Tx-birdcage/32Rx-loops array. Simulated and measured B + 1 maps were shown for the 8Tx-dipoles/32Rx-loops coil array and compared with the 8Tx/Rx dipole array. Results : The in-house built 32-channel receive coil demonstrated a large longitudinal coverage of the brain, particularly the upper neck area. G-factors and accelerated MR acquisitions demonstrated robust performances up to R = 4 in 2D, and R = 8 (4 × 2) in 3D. A 83% increase in SNR was measured over the cerebellum with the in-house built 8Tx/32Rx coil array compared to the commercial 1Tx/32Rx, while similar performances were obtained in the cerebral cortex. Conclusions : The combined 32-channel receive/8-channel transmit coil array demonstrated high transmit-receive performances compared to the commercial receive array at 7T, notably in the cerebellum. We conclude that in combination with parallel transmit capabilities, this coil is particularly suitable for whole-brain MR studies at 7T.

AB - Purpose : Multichannel receive arrays provide high SNR and parallel-imaging capabilities, while transmit-only dipole arrays have been shown to achieve a large coverage of the whole-brain including the cerebellum. The aim of this study was to develop and characterize the performances of a 32-channel receive-only loop array combined with an 8-channel dipole coil array at 7T for the first time. Methods : The 8Tx-dipoles/32Rx-loops coil array was characterized by the SNR, g-factors, noise correlation matrix, accelerated image quality, and B + 1 maps, and compared with a commercial 1Tx-birdcage/32Rx-loops array. Simulated and measured B + 1 maps were shown for the 8Tx-dipoles/32Rx-loops coil array and compared with the 8Tx/Rx dipole array. Results : The in-house built 32-channel receive coil demonstrated a large longitudinal coverage of the brain, particularly the upper neck area. G-factors and accelerated MR acquisitions demonstrated robust performances up to R = 4 in 2D, and R = 8 (4 × 2) in 3D. A 83% increase in SNR was measured over the cerebellum with the in-house built 8Tx/32Rx coil array compared to the commercial 1Tx/32Rx, while similar performances were obtained in the cerebral cortex. Conclusions : The combined 32-channel receive/8-channel transmit coil array demonstrated high transmit-receive performances compared to the commercial receive array at 7T, notably in the cerebellum. We conclude that in combination with parallel transmit capabilities, this coil is particularly suitable for whole-brain MR studies at 7T.

KW - 32-channel

KW - parallel imaging

KW - phased array

KW - SNR

KW - transmit dipoles

KW - ultra-high field

UR - http://www.scopus.com/inward/record.url?scp=85065789492&partnerID=8YFLogxK

U2 - 10.1002/mrm.27808

DO - 10.1002/mrm.27808

M3 - Article

AN - SCOPUS:85065789492

SN - 0740-3194

VL - 82

SP - 1229

EP - 1241

JO - Magnetic Resonance in Medicine

JF - Magnetic Resonance in Medicine

IS - 3

ER -