The iPRES-W Coil: Advancements in Wireless Technology for Magnetic Resonance Imaging

Truong, Trong-Kha

Darnell, Dean

Cuthbertson, Jonathan

2022-06-15T18:43:18Z

2022

Medical Physics

AbstractPurpose: Integration of wireless data transfer in magnetic resonance imaging (MRI) would allow for the reduction of wired connections between the scanner subsystems and the control computers located outside the scanner room, which add to the cost and complexity of the scanner, reduce patient comfort, and impede the application of next-generation MRI technologies.

Methods:In this dissertation, a novel RF coil design, termed the wireless integrated parallel reception, excitation, and shimming (iPRES-W) coil design, is further developed to remove some of these wired connections by offering a compact and easy-to-integrate MR-compatible wireless data transfer solution, which requires no scanner modifications or additional antenna systems in the bore. The iPRES-W coil design allows both a direct current (DC) and radio-frequency (RF) currents at the Larmor frequency and in a wireless communication band to flow on the same coil element to enable simultaneous MR image acquisition and wireless data transfer, which enables: wireless localized B0 shimming; wireless peripheral system data transfer to augment imaging (e.g., respiratory tracking using a respiratory belt); wireless transfer of the scanner control signal to control on-coil electronics (e.g., Q-spoiling); and wireless power harvesting to power components of the iPRES-W system. To demonstrate the performance and utility of the iPRES-W coil design in clinically relevant applications, this dissertation has four aims: 1. To develop an iPRES-W spine coil array to perform simultaneous MR imaging and wireless localized B0 shimming of the spinal cord; 2. To develop a dual-stream iPRES-W head coil array for simultaneous MR imaging of the brain and multiple wireless data streams for control of separate peripheral systems, specifically, wireless localized B0 shimming and respiratory tracking using a respiratory belt; 3. To further develop an integrated RF/wireless coil design for wireless transfer of the scanner trigger signal to perform the Q-spoiling required for MR image acquisition; 4. To design a wireless power harvesting system to convert the high-energy RF energy emitted by the scanner during the transmit cycle into a DC voltage to charge the batteries to power in-bore electronics and B0 shim currents.

Results:The results from this dissertation demonstrate that the iPRES-W coil modifications did not degrade the signal-to-noise ratio (SNR) when implemented onto different radio-frequency coil structures (e.g., a conventional RF coil element and novel adaptive imaging receive (AIRTM) coil element). Wireless localized B0 shimming with the iPRES-W spine array and dual-stream iPRES-W head coil array substantially reduced the B0 root-mean-square-error (RMSE) by 70.1% and -41.2% in the spinal cord and frontal brain region, which corresponded to reduced DTI and EPI distortions, respectively. The wireless performance of the iPRES-W and iRFW coil elements measured in an anechoic chamber were minimally impacted by the introduction of a saline phantom representing tissue or during wireless Q-spoiling, respectively. The power harvesting experiments performed showed that the 4-channel power harvesting coil array could convert RF energy from the scanner into a DC voltage for recharging MR-compatible batteries for various scan parameters and imaging sequences.

Conclusions:The iPRES-W and iRFW coil designs can be integrated into different coil structures and arrays to perform simultaneous imaging, wireless localized B0 shimming, and wireless transfer of peripheral device data (e.g., respiratory tracking with a respiratory belt), with no SNR degradation, minimal change in wireless performance, and without scanner modifications or additional antenna systems within the scanner bore. Additionally, the power harvesting array can supply wireless power to charge MR-compatible batteries for various scan types and parameters.

https://hdl.handle.net/10161/25208

Medical imaging

Engineering

Imaging

iPRES

iPRES-W

MRI

Shimming

Wireless

The iPRES-W Coil: Advancements in Wireless Technology for Magnetic Resonance Imaging

Dissertation

23.375342465753423

2024-05-26T00:00:00Z