Improved Longitudinal Coverage For Human Brain At 7T: A 16 Element Transceiver Array

Nikolai I. Avdievich¹, Jullie W. Pan¹, Hoby P. Hetherington¹

At 7T, interactions between the human brain and RF result in poor homogeneity and efficiency when volume coils are used for transmission. Although short (9cm) transceiver arrays can dramatically improve both axial homogeneity and efficiency (17uT/kW) using RF shimming, coverage in the longitudinal direction is limited. Increasing the length of the array to 15cm provides only modest improvements in longitudinal coverage at the cost of significant decreases in sensitivity and transmit efficiency. To overcome this limitation we have developed an inductively decoupled 16 coil transceiver array, with the individual coils arranged in two rows along the z-axis of 8 coils each (2x8 array). The array provides dramatically improved longitudinal coverage and SNR while retaining high efficiency.