Advancing Free-Breathing Liver MRI at 7T with Pseudo-Spiral Cartesian Sampling and Phase-Shimming

Motivation: Ultra-high field (B0 ≥ 7T) MRI potentially offers high spatial resolution. However, 7T abdominal MRI is challenging due to B1+-inhomogeneities and patients’ breath-holding limits, especially for high-resolution scans. Goal(s): To develop a high-quality, free-breathing liver scan at 7T. Approach: We implemented a 3D-GRE with golden-angle pseudo-spiral sampling pattern at 7T, that allowed respiratory binning in a free-breathing acquisition followed by Compressed Sensing reconstruction. Phase-shimming was used to achieve a homogeneous signal intensity over the liver. Results: We successfully achieved 1.35x1.35x1.35mm3-resolution liver images with high image quality, including signal homogeneity over the entire liver, demonstrating the potential of free-breathing 7T liver MRI. Impact: This study addresses breath-holding and B1+-inhomogeneity challenges associated with 7T abdominal MRI. It could further the development of non-invasive and detailed liver visualization. Ultimately, this would alter clinical pathways and offer patients a more comfortable imaging experience.