Free-breathing non-contrast MRA with efficiency-adaptive self navigation

Background Non-contrast MRA (NC-MRA) based on bSSFP and slab-selective inversion has become an attractive alternative for imaging renal arteries without the usage of potentially nephrotoxic contrast agent. It typically requires navigator gating or abdominal bellow triggering to alleviate breathing motion artifacts. However, navigator gating significantly complicates and lengthens exams due to its setup, adjusting, and scout scans. It also causes signal loss in renal arteries due to cross-pair saturation bands. Abdominal bellow triggering increases patient preparation time and disables the usage of ECG triggering leading to suboptimal inflow effect. In this work, a novel self navigation (SN) technique is developed in an attempt to overcome the limitations of the aforementioned free-breathing methods while maintaining scanning efficiency.