Michael D. Twieg

Active Detuning of MRI Receive Coils with GaN FETs

Here, we present the use of Gallium Nitride (GaN) FETs as a replacement for PIN diodes in active detuning circuits for magnetic resonance imaging (MRI) receive coils at 63.6 MHz. We use simulated circuit models, benchtop measurements, and imaging experiments to show that GaN FETs perform comparably with a common MRI-compatible PIN diode. The GaN FET-based circuits require orders of magnitude less bias current to operate, effectively eliminating B0 distortion resulting from biasing.

Identification and mitigation of interference sources present in SSB-based wireless MRI receiver arrays

Single sideband amplitude modulation (SSB) is an appealing platform for highly parallel wireless MRI detector arrays because the spacing between channels is ideally limited only by the MRI signal bandwidth. However this assumes that no other sources of interference are present outside that bandwidth. This work investigates the practical interference between multiple SSB‐encoded MRI signals.

High efficiency radiofrequency power amplifier module for parallel transmit arrays at 3 Tesla

The purpose of this study is to develop an in‐bore radiofrequency (RF) power amplifier (RFPA) module with high power efficiency and density for use in parallel transmit (pTX) arrays at 3 Tesla.

Device localization and dynamic scan plane selection using a wireless magnetic resonance imaging detector array.

A prototype wireless guidance device using single sideband amplitude modulation (SSB) is presented for a 1.5T magnetic resonance imaging system.

Device localization and dynamic scan plane selection using a wireless MRI detector array

A prototype wireless guidance device using single sideband amplitude modulation (SSB) is presented for a 1.5T magnetic resonance imaging system.

Device localization and dynamic scan plane selection using a wireless magnetic resonance imaging detector array: Device Localization Using a Wireless MRI Array

A prototype wireless guidance device using single sideband amplitude modulation (SSB) is presented for a 1.5T magnetic resonance imaging system.