Bilateral breast gradient insert prototype for strong diffusion encoding at 3T

TL;DR

This paper presents a cost-effective, high-performance bilateral breast gradient insert designed to enable strong-gradient diffusion MRI at 3T, facilitating breast cancer imaging without contrast agents.

Contribution

Development and evaluation of a novel, commercially built bilateral breast gradient insert compatible with existing MRI systems for enhanced diffusion imaging.

Findings

Gradient efficiency of 2.8 mT/m/A enabling 1850 mT/m local strength

No peripheral nerve stimulation observed in volunteer tests

Feasibility of high b-value imaging with reduced echo time (78 ms)

Abstract

Purpose: Diffusion MRI has shown promise for breast cancer screening, lesion characterization,and treatment response monitoring without contrast agents, but further translation is constraint by the gradient performance of conventional systems. The aim of this work is to develop a single-axis high performance bilateral plug-and-play breast gradient insert to enable strong-gradient diffusion MRI. Methods: An in-house breast gradient insert and bed-tabletop was constructed entirely from commercially available materials, providing a cost-effective solution compatible with existing MRI systems. Its wiring pattern was optimized for torque and force balancing, power dissipation, and target field performance. Evaluation included gradient field characterization, peripheral nerve stimulation simulation verification, and temperature and eddy current assessment. The setup was used for imaging of a diffusion phantom based on soy lecithin across a range of b-values. Results: Gradient efficiency reached 2.8 mT/m/A, enabling local strengths up to 1850 mT/m (660 A). No peripheral nerve stimulation was observed during tests on five healthy volunteers. Eddy currents were successfully characterized employed in standard correction methods. Imaging showed the feasibility of $b = 10 000 s/mm^2$ acquisitions at TE = 78 ms versus 161 ms with scanner gradients. Conclusion: This work demonstrates a dedicated bilateral breast gradient insert for safe and feasible strong-gradient breast diffusion MRI, and represents a first step toward dedicated hardware for breast cancer detection and characterization without contrast agents.