An iPRES-W Coil Array for Simultaneous Imaging and Wireless Localized B 0 Shimming of the Cervical Spinal Cord
Jonathan D. Cuthbertson, Trong-Kha Truong, Robert Stormont, Fraser Robb, Allen W. Song, Dean Darnell
Abstract
Purpose
To develop a wireless integrated parallel reception, excitation, and shimming (iPRES-W) coil array for simultaneous imaging and wireless localized B 0 shimming, and to demonstrate its ability to correct for distortions in DTI of the spinal cord in vivo.
Methods
A 4-channel coil array was modified to allow an RF current at the Larmor frequency and a direct current to flow on each coil element, enabling imaging and localized B 0 shimming, respectively. One coil element was further modified to allow additional RF currents within a wireless communication band to flow on it to wirelessly control the direct currents for shimming, which were supplied from a battery pack within the scanner bore. The RF signals for imaging were transferred via conventional wired connections. Experiments were conducted to evaluate the RF, B 0 shimming, and wireless performance of this coil design.
Results
The coil modifications did not degrade the SNR. Wireless localized B 0 shimming with the iPRES-W coil array substantially reduced the B 0 RMSE (−57.5% on average) and DTI distortions in the spinal cord. The antenna radiation efficiency, antenna gain pattern, and battery power consumption of an iPRES-W coil measured in an anechoic chamber were minimally impacted by the introduction of a saline phantom representing tissue.
Conclusion
The iPRES-W coil array can perform imaging and wireless localized B 0 shimming of the spinal cord with no SNR degradation, with minimal change in wireless performance and without any scanner modifications or additional antenna systems within the scanner bore.