Simulations of an Integrated RF/Wireless Coil Design for Simultaneous Magnetic Resonance Image Acquisition and Data Transfer

A novel integrated RF/wireless coil design, termed an integrated RF/wireless coil, which enables simultaneous MR image acquisition and wireless data transfer, has recently been proposed. The integrated RF/wireless coil design allows radio-frequency (RF) currents to flow on the coil simultaneously at the Larmor frequency, for MR image acquisition, and at the 2.4 GHz wireless communication frequency, for wireless data transfer from within the MRI scanner bore to a wireless Access Point (AP) on the scanner room wall. The integrated RF/wireless coil design provides a low-cost solution for wireless data transmission between the scanner bore and the console room that requires no mechanical modifications to the existing MRI system, which can 1) reduce the need for cumbersome cabling networks in the scanner, 2) increase patient comfort, and 3) decrease patient set up time.

In previous work, the radiated energy emitted from the integrated RF/wireless coil was not optimized for wireless data transfer between the coil in the scanner bore and the AP on the scanner room wall. The wireless data transfer from an integrated RF/wireless coil is optimal when the maximum amount of radiated power in the wireless communication band is transferred from the integrated RF/wireless coil to the AP, and the power deposited into the subject in the scanner is minimized. However, measurements of the radiated power from the integrated RF/wireless coil in the MRI environment (i.e., in the scanner bore and on a human) are not practical because they would require an excessively large anechoic chamber. Thus, electromagnetic simulations are performed to determine the optimal integrated RF/wireless coil design (e.g., size, position on the subject) that maximizes the radiated power delivered from the coil to an AP while 1) ensuring no degradation in SNR compared to a traditional RF coil and 2) minimizing the radiated power deposited into the subject in the scanner bore.

In this work, 3-D finite element electromagnetic co-simulations with an RF circuit designer are performed to optimize the gain of an integrated RF/wireless coil on a human phantom in the scanner bore and the corresponding S21 power transmission (i.e., link budget) between the coil and an AP on the scanner room wall. These simulations are verified by constructing an integrated RF/wireless coil and by using it to perform free-space radiated gain pattern measurements in an anechoic chamber and to acquire SNR maps of a uniform water phantom in an MRI scanner.