Self-navigated 3D multi-slab EPI for SNR-efficient high-resolution diffusion MRI

Motivation: 3D multi-slab EPI achieves superior SNR efficiency for high-resolution diffusion MRI but requires navigators for phase correction, which increase scan time and SAR. Goal(s): To eliminate the requirement for navigators in 3D multi-slab diffusion MRI. Approach: 3D imaging is intrinsically highly segmented, making self-navigation challenging. Our optimized multi-shot sampling facilitates self-navigation by ensuring each shot intersects with kz=0 plane. The overall sampling pattern’s overlap and gaps are also minimized. A structured low-rank reconstruction is leveraged to reconstruct 2D phase maps from these intersections for phase correction. Results: Compared to navigated imaging our self-navigated method achieves comparable image quality with 31.4% shorter scan time. Impact: By removing the need for navigation, our method enables 3D multi-slab diffusion MRI to efficiently achieve TRs with near-optimal SNR efficiency. This approach may permit wider adoption of high-resolution diffusion MRI for basic and clinical neuroscience.