Optimized parallel transmit and receive radiofrequency coil for ultrahigh-field MRI of monkeys

Towards HCP-Style Macaque Connectomes: 24-Channel 3T Multi-Array Coil, MRI Sequences and Preprocessing

“…1B, D). This geometrical arrangement yields a relatively small noise 682 correlation coefficient (0.084), which is smaller than in previous macaque multi-channel coil designs 683 such as 0.12 in a 24-channel (Gilbert et al, 2016) and 0.22 in a 22-channel (Janssens et al, 2013). Our 684 coil design together with slice and in-plane accelerated imaging allowed up to five-fold and two-by-685 two (MB-by-GRAPPA) accelerations for fMRI and dMRI, respectively.…”

In vivo proton observed carbon edited (POCE) 13C magnetic resonance spectroscopy of the rat brain using a volumetric transmitter and receive‐only surface coil on the proton channel

“…However, 13 C labeled metabolites observed in dynamic 1 H‐ 13 C MRS studies reside in a spectral window of ∼2.6 ppm (1.3–3.9 ppm), hence CSDE is reduced to < 20%. If CSDE is a limitation at higher field strengths, a few modifications to the platform can be exploited: (i) use peak‐ constrained optimal control high bandwidth refocusing pulses ; (ii) replace the volumetric 1 H resonator with a smaller (head‐only) detunable volumetric resonator to achieve higher peak ; or (iii) at ultra‐high field strengths when the field of view dimensions approach the RF wavelength (∼ λ/2), a detunable transmit array coil can be used in combination with parallel transmit or rf shimming approaches to improve .…”

“…However, 13 CSDE is reduced to < 20%. If CSDE is a limitation at higher field strengths, a few modifications to the platform can be exploited: (i) use peak-B þ 1 constrained optimal control high bandwidth refocusing pulses (40,41); (ii) replace the volumetric 1 H resonator with a smaller (head-only) detunable volumetric resonator to achieve higher peak B þ 1 ; or (iii) at ultra-high field strengths when the field of view dimensions approach the RF wavelength ($ l/2), a detunable transmit array coil can be used in combination with parallel transmit or rf shimming approaches to improve B þ 1 (42,43). In addition to the use of RF filters, further attenuation of heteronuclear decoupling signals from coupling to the 1 H channel was achieved with double shielded coax cables, and strategically placing 13 C baluns on all RF carrying cables.…”

A macaque connectome for large-scale network simulations in TheVirtualBrain

“…Images were acquired using a 7-T Siemens MAGNETOM head scanner with an in-house designed and manufactured coil optimized for the non-human primate head 46 . Two diffusion weighted scans were acquired for each animal, with each scan having opposite phase encoding in the superior-inferior direction at 1 mm isotropic resolution.…”