Quantitative T1rho with pulsed spinlock Using Toggling Inversion Preparation

Motivation: Conventional T1rho techniques require sufficiently long TSL (time of spinlock) to ensure reliable T1rho quantification, However, maximum TSL allowed in clinical MR scanners is often limited by SAR (specific absorption rate) and RF amplifier to ensure patient safety and prevent damage to the scanners. Goal(s): Our proposed toggling inversion preparation pulsed spinlock mitigates the problem by employing a train of spinlock pulses with a gap duration between two pulses. Approach: We Confirmed our conjectures using simulation, phantom, and in vivo experiment. Results: Our approach can achieve reliable T1rho quantification using longer TSL compared to the conventional spinlock technique. Impact: The Proposed method has potential to enable T1rho imaging of tissue with relatively long relaxation time and at MRI system where continus spin-lock is challenging.