Highly accelerated time-resolved 4D MRA using stack-of-stars golden-angle radial acquisition and subtraction-based subspace reconstruction

Motivation: ASL-based time-resolved 4D MRA potentially suffers from temporal blurring when accelerating image acquisition by exploiting temporal correlations. Goal(s): To develop a robust 4D MRA reconstruction framework that enables a very high acceleration rate while preserving good temporal fidelity. Approach: We developed a fast low-rank subspace high-resolution 4D MRA (Flash-4D-MRA) that combines SOS golden-angle radial sampling with joint subtraction-based self-calibrated low-rank subspace and magnitude-subtraction sparsity constraint to achieve an ultra-high temporal resolution. Each 4D MRA data was reconstructed with four high acceleration rates. Results: Dynamic MRA images were successfully reconstructed using Flash-4D-MRA with higher acceleration rates without compromising temporal fidelity. Impact: Flash-4D-MRA allows for the delineation of cerebral dynamic flow with good image quality and temporal fidelity at an ultra-high temporal resolution, which could be a potentially useful non-contrast 4D MRA technique in clinical applications to characterize fast-flow events.