gr-MRI is a software package that enables the development of custom MRI spectrometers using off-the-shelf software-defined radios.
Christopher J Hasselwander1,2, William A Grissom1,2
Purpose: To enable the rapid implementation of custom MRI spectrometers using commercially-available software defined radios (SDRs), without requiring hardware or FPGA programming expertise.
Description: The gr-MRI software package comprises a set of Python scripts, flowgraphs, and signal generation and recording blocks for GNU Radio, an open-source SDR software package that is widely used in communications research. gr-MRI Implements basic event sequencing functionality, and tools for system calibrations, multi-radio synchronization, and MR signal processing and image reconstruction. It includes four pulse sequences: a single-pulse sequence to record free induction signals, a gradient-recalled echo imaging sequence, a spin echo imaging sequence, and a spin echo inversion recovery imaging sequence.
Validations: We have validated the gr-MRI sequences in phantom imaging scans with a 0.5 Tesla tabletop MRI scanner and two commercially-available SDRs. One SDR was used for RF excitation and reception, and the other for gradient pulse generation. The total SDR hardware cost was approximately $2000. We have also validated the SDR’s ability to generate frequency-swept RF waveforms, which may be important for RF encoding.
1Department of Biomedical Engineering, Vanderbilt University, Nashville, Tennessee, USA
2Vanderbilt University Institute of Imaging Science, Nashville, Tennessee, USA