An 8-channel receive array for improved 31 P MRSI of the whole brain at 3T.

PURPOSE: To demonstrate a 1 H/31 P whole human brain volume coil configuration for 3 Tesla with separate 31 P transmit and receive components that maintains 1 H MRS performance and delivers optimal 31 P MRSI with 1 H decoupling. METHODS: We developed an 8-channel 31 P receive array coil covering the head to be used as an insert for a commercial double-tuned 1 H/31 P birdcage transmit-receive coil. This retains the possibility of using low-power rectangular pulses for 1 H-decoupled 3D 31 P MRSI (nominal resolution 17.6 cm3 ; acquisition duration 13 min) but increases the SNR with the receive sensitivity of 31 P surface coils. The performance of the combined coil setup was evaluated by measuring 1 H and 31 P SNR with and without the 31 P receive array and by assessing the effect of the receive array on the transmit efficiencies of the birdcage coil. RESULTS: Compared to the birdcage coil alone, the 31 P insert in combination with the birdcage achieved an average 31 P SNR gain of 1.4 ± 0.4 in a center partition of the brain. The insert did not cause losses in 1 H MRS performance and transmit efficiency, whereas for 31 P approximately 20% more power was needed to achieve the same γB1. CONCLUSION: The new coil configuration allows 1 H MRSI and optimal 1 H-decoupled 3D 31 P MRSI, with increased SNR of the human brain without patient repositioning, for clinical and research purposes at 3 Tesla.