Spiral Time Resolved Imaging (SPTI)

Motivation: Spiral is the most efficient k-space coverage strategies in current MR gradient systems with robustness to motion and flow, but the implementation of long spiral trajectories keeps challenging due to accumulated off resonance effect and local susceptibility. Goal(s): SPTI is proposed for artifact- and distortion-free spiral imaging and quantification. Approach: Modified segmented spiral readout and subspace reconstruction were performed in SPTI technique. Results: SPTI sequence was validated in a phantom study and feasibility was evaluated on a brain volunteer. In human study, SPTI method showed consistent results with MRF-EPTI on quantitative mapping, including PD, T1, T2 and T2*. Impact: SPTI method can simultaneously quantify PD, T1, T2 and T2* mapping and is potential to expand to other body regions, especially in the liver and cardiac MRI.