Spherical Echo-Planar Time-resolved Imaging (sEPTI) for rapid 3D quantitative T2* and susceptibility imaging

Motivation: To improve the quality, resolution, and SNR, and reduce scan time by reducing averages for T2* and QSM at 3T Goal(s): To develop a sEPTI technique that can achieve submillimeter high-quality T2* and QSM quantification in less than 90 seconds. Approach: We developed: (1) an efficient less-correlated spherical EPTI sampling d; (2) an iterative B0 update pipeline for accurate and high SNR B0 map; (3) eddy-current correction to reduce artifacts; (4) a physics-informed unrolled network to boost the SNR. Results: sEPTI achieved whole-brain 0.75-mm T2* and QSM quantification within a 90-second scan with the potential for wide clinical applications. Impact: sEPTI technique was developed with synergetic improvements in sampling, B0 estimation, eddy-current correction, and unrolled-network reconstruction, which achieves whole-brain 0.75-mm distortion-free and blurring-free T2* and QSM quantification at 3T in 90 seconds with the potentials for wide clinical applications.