Prostate Diffusion-Weighted Imaging with an Inside-Out Nonlinear Gradient Coil

Motivation: Widely used to diagnose prostate cancer, diffusion-weighted imaging (DWI) is limited by gradient strength. As an alternative to costly whole-body strong-gradient scanners, we proposed an insertable inside-out nonlinear gradient coil tailored for the prostate. Goal(s): Achieve the required diffusion weighting in the prostate with high signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR). Approach: We developed DWI methods for the nonlinear gradient, including eddy current correction and design of diffusion encoding scheme. Results: The nonlinear gradient reduces echo time (42ms vs. 57ms or 72ms), enhances prostate SNR, and shows promise for high lesion CNR. Impact: The proposed inside-out nonlinear gradient coil provides easy access to strong gradient for high-SNR and high-CNR prostate DWI, which can be flexibly installed for clinical scanners and facilitates triage, diagnosis, and surveillance of prostate cancer.