Engineering clinical translation of OGSE diffusion MRI

Area of Science:

• Medical Imaging
• Biophysics
• Neuroscience

Background:

• Oscillating gradient spin echo (OGSE) diffusion MRI (dMRI) offers sensitivity to tissue microstructure at short length scales ($$ m) by probing diffusive dynamics on short time scales (≲10 ms).
• Pre-clinical studies have established OGSE-based techniques for characterizing cell diameter and cellular density, demonstrating potential in differentiating tumor types, assessing treatment effectiveness, and understanding neurological diseases.
• Recent advancements in high-performance gradient human MRI systems create opportunities to translate OGSE findings from pre-clinical research to human studies and clinical applications.

Purpose of the Study:

• To review the challenges and considerations for implementing OGSE dMRI in human studies.
• To summarize the impact of hardware and human biophysical safety factors on OGSE waveform design, imaging parameters, and image quality.
• To highlight the potential of OGSE dMRI to advance understanding of human brain microstructure and improve patient care.

Main Methods:

• Review of hardware and human biophysical safety considerations impacting OGSE dMRI waveform design.
• Discussion of factors including gradient amplitude, slew rate, peripheral nerve and cardiac stimulation, gradient driver limitations, acoustic noise, mechanical vibration, eddy currents, gradient nonlinearity, concomitant gradients, motion, flow, and signal-to-noise ratio.
• Analysis of engineering requirements for safe, high-quality, and reproducible OGSE dMRI in human subjects.

Main Results:

• Engineering OGSE diffusion encoding for human imaging presents significant challenges compared to conventional pulsed gradient spin echo methods.
• Various hardware and safety factors critically influence the achievable imaging parameter space and overall image quality.
• Understanding and mitigating these factors are essential for successful translation.

Conclusions:

• Targeted engineering efforts focused on safety, quality, and reproducibility are crucial for enabling the clinical translation of OGSE dMRI techniques.
• Successful implementation of OGSE dMRI in humans promises to enhance the study of brain microstructure and improve diagnostic capabilities for neurological conditions.
• Overcoming engineering hurdles will unlock the full potential of OGSE dMRI for both research and clinical practice.