Optimized (31) P MRS in the human brain at 7hspace0.167emT with a dedicated RF coil setup.

NMR Biomed
2015
1570--1578
B. van de Bank, S. Orzada, F. Smits, M. Lagemaat, C. Rodgers, A. Bitz and T. Scheenen

The design and construction of a dedicated RF coil setup for human brain imaging ((1) H) and spectroscopy ((31) P) at ultra-high magnetic field strength (7 T) is presented. The setup is optimized for signal handling at the resonance frequencies for (1) H (297.2 MHz) and (31) P (120.3 MHz). It consists of an eight-channel (1) H transmit-receive head coil with multi-transmit capabilities, and an insertable, actively detunable (31) P birdcage (transmit-receive and transmit only), which can be combined with a seven-channel receive-only (31) P array. The setup enables anatomical imaging and (31) P studies without removal of the coil or the patient. By separating transmit and receive channels and by optimized addition of array signals with whitened singular value decomposition we can obtain a sevenfold increase in SNR of (31) P signals in the occipital lobe of the human brain compared with the birdcage alone. These signals can be further enhanced by 30 ± 9\% using the nuclear Overhauser effect by B1 -shimmed low-power irradiation of water protons. Together, these features enable acquisition of (31) P MRSI at high spatial resolutions (3.0 cm(3)  voxel) in the occipital lobe of the human brain in clinically acceptable scan times (~15 min). © 2015 The Authors. NMR in Biomedicine published by John Wiley & Sons Ltd.
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