A self‐decoupled 32‐channel receive array for human‐brain MRI at 10.5 T

Abstract

Purpose Receive array layout, noise mitigation, and B0 field strength are crucial contributors to SNR and parallel‐imaging performance. Here, we investigate SNR and parallel‐imaging gains at 10.5 T compared with 7 T using 32‐channel receive arrays at both fields. Methods A self‐decoupled 32‐channel receive array for human brain imaging at 10.5 T (10.5T‐32Rx), consisting of 31 loops and one cloverleaf element, was co‐designed and built in tandem with a 16‐channel dual‐row loop transmitter. Novel receive array design and self‐decoupling techniques were implemented. Parallel imaging performance, in terms of SNR and noise amplification (g‐factor), of the 10.5T‐32Rx was compared with the performance of an industry‐standard 32‐channel receiver at 7 T (7T‐32Rx) through experimental phantom measurements. Results Compared with the 7T‐32Rx, the 10.5T‐32Rx provided 1.46 times the central SNR and 2.08 times the peripheral SNR. Minimum inverse g‐factor value of the 10.5T‐32Rx (min[1/g] = 0.56) was 51% higher than that of the 7T‐32Rx (min[1/g] = 0.37) with R = 4 × 4 2D acceleration, resulting in significantly enhanced parallel‐imaging performance at 10.5 T compared with 7 T. The g‐factor values of 10.5 T‐32 Rx were on par with those of a 64‐channel receiver at 7 T (eg, 1.8 vs 1.9, respectively, with R = 4 × 4 axial acceleration). Conclusion Experimental measurements demonstrated effective self‐decoupling of the receive array as well as substantial gains in SNR and parallel‐imaging performance at 10.5 T compared with 7 T.

Lowering the Thermal Noise Barrier in Functional Brain Mapping with Magnetic Resonance Imaging

“…0.46 or ~0.5 mm isotropic resolution). We demonstrate here that this goal is achieved with NORDIC (Figure 6) at 7 Tesla and likely will soon be surpassed when multiplicative gains will be attained combining NORDIC with additional independent gains from acquisition methods, higher magnetic fields 52 , high channel count RF coils employed synergistically with very high magnetic fields 53,54 and image reconstructions methods (e.g. 55,56 ).…”

Lowering the thermal noise barrier in functional brain mapping with magnetic resonance imaging

“…We demonstrate here that this goal is achieved with NORDIC (Fig. 6) at 7 T and likely will soon be surpassed when multiplicative gains will be attained combining NORDIC with additional independent gains from acquisition methods, higher magnetic fields 52 , high channel count RF coils employed synergistically with very high magnetic fields 53,54 and image reconstructions methods (e.g. refs.…”

A Review of the Recent Advances in Ultra-High Field Magnetic Resonance Imaging

“…These studies have shown improvements in simulations and have a promising prospect once they are fully implemented experimentally. These increases in signal-to-noise ratio (such as reported in [26]) are substantial progress towards empowering neuroscience research applications targeting human brain [31].…”

“…Most recently, the concept of self-decoupling was introduced [25]. Other researchers [26] brilliantly developed the self-decoupling concept to simplify the design of receive arrays and also demonstrated experimentally that self-decoupling provides an SNR advantage compared to overlap-decoupling. The latter stands as a much anticipated breakthrough that obviates the complexities of building high density receive arrays.…”