A radially interleaved sodium and proton coil array for brain MRI at 7 T
Bili Wang, Bei Zhang, Zidan Yu, Carlotta Ianniello, Karthik Lakshmanan, Jan Paška, Guillaume Madelin, Martijn A. Cloos, Ryan Brown
Abstract
The objective of the current study was to design and build a dual‐tuned coil array for simultaneous 23 Na/ 1 H MRI of the human brain at 7 T. Quality factor, experimental B 1 + measurements, and electromagnetic simulations in prototypes showed that setups consisting of geometrically interleaved 1 H and 23 Na loops performed better than or similar to 1 H or 23 Na loops in isolation. Based on these preliminary findings, we built a transmit/receive eight‐channel 23 Na loop array that was geometrically interleaved with a transmit/receive eight‐channel 1 H loop array. We assessed the performance of the manufactured array with mononuclear signal‐to‐noise ratio (SNR) and B 1 + measurements, along with multinuclear magnetic resonance fingerprinting maps and images. The 23 Na array within the developed dual‐tuned device provided more than 50% gain in peripheral SNR and similar B 1 + uniformity and coverage as a reference birdcage coil of similar size. The 1 H array provided good B 1 + uniformity in the brain, excluding the cerebellum and brain stem. The integrated 23 Na and 1 H arrays were used to demonstrate truly simultaneous quantitative 1 H mapping and 23 Na imaging.