arXiv subjects

Feng Jia

Publications and source records attributed to Feng Jia.

3 recordsLinked to original sources

arXiv2026

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

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.

physics.med-ph↗

arXiv2026

Design of a double breast gradient coil with controlled anterior posterior gradient variation for diffusion weighted imaging

Introduction High performance gradients poses a promise for breast diffusion weighted imaging (DWI) but are restricted by physiological limits in whole body scanners. While local nonlinear coils offer higher amplitudes, they often suffer from severe gradient reduction near the chest wall. Methods We introduced an optimization framework incorporating a constraint to control anterior posterior gradient variation. A width based figure of merit was defined to evaluate performance regarding coil efficiency and minimum wire width. A prototype was constructed to validate the design methodology. Results The optimized coil achieved a 2.35 fold efficiency increase over standard linear coils. Compared to previous nonlinear designs, the new constraint reduced spatial variation by 35.7% and improved minimum efficiency near the chest wall by 2.6 fold. Experimental field maps matched simulations with errors under 8%. Discussion The proposed method effectively mitigates the trade-off between gradient strength and spatial uniformity along anterior posterior direction. By enhancing performance in the posterior breast region, the design addresses a critical limitation of previous local coils. Conclusion This framework enables the development of high performance, robust local gradient coils, facilitating the clinical implementation of advanced DWI protocols for breast cancer screening.

physics.med-ph↗

arXiv2020

Design of a non-linear human breast diffusion coil

Diffusion-weighted imaging (DWI) in the female breast is a magnetic resonance imaging (MRI) technique, which may potentially replace or effectively complement both x-ray mammography and contrast-enhanced MR mammography. To further improve specificity of DWI in the breast, stronger and faster diffusion weighting is advantageous. With the target application in mind, the gradient coil is designed on an irregularly shaped semi-open current-carrying surface. Due to the coil former closely fitting the non-spherical target region, non-linear encoding fields become particularly advantageous for achieving locally exceptionally high gradient strengths. As the breast tissue has a predominantly isotropic cellular microstructure, the direction of the diffusion-weighting gradient may be allowed to vary within the target volume. However, due to the quadratic dependency of the b-factor on the gradient strength, variation of the gradient magnitude needs to be carefully controlled. To achieve the above design goals the corresponding multi-objective optimization problem is reformulated as a constrained optimization, allowing for flexible and precise control of the coil properties. A novel constraint is proposed limiting the gradient magnitude variation within every slice while allowing for variations both the direction of the gradient within the slice and the magnitude across the slices. The above innovations enable the design of a unilateral coil for diffusion weighting in the female breast with the local gradient strengths exceeding 1~T/m with highly homogeneous diffusion weighting for imaging in the coronal slice orientation.

physics.med-ph↗