Influence of spin-locking direction on T1rho quantification: evaluation in phantoms with and without T1rho dispersion property

Motivation: B0 and B1 inhomogeneities play a critical role in T1ρ preparation due to their strong impact on the fidelity of the resultant spin-locking. However, their influence on samples with T1ρ dispersion has not been fully investigated. Goal(s): Evaluate the impact of B0 inhomogeneity on T1rho. Approach: Phantoms without or with T1rho dispersion characteristic (agarose only, agarose+glucose, respectively) were scanned with T1rho preparation proposed by Chen, with a range of added B0 inhomogeneity. Results: We observed different measured T1rho time with the size and polarity of B0 offset related to the on-resonance T1rho dispersion characteristic at the effective B1 magnitude. Impact: A newly documented phenomenon on the T1rho preparation on different B0 inhomogeneity with magnetization locked to the effective B1 presents a new question on how to handle T1rho imaging with added inhomogeneity.