Optimization of spin-lock times for T_1ρ mapping of human knee cartilage with bi- and stretched-exponential models.

ABSTRACT: Two optimization criteria based on Cramér-Rao Bounds are compared between each other and with non-optimized schedules for T_1ρ mapping using synthetic data, model phantoms, and in-vivo knee cartilage. The curve fitting is done on complex-valued data using an iterative Nonlinear Least Squares (NLS) approach. The optimization criteria are compared based on the Mean Normalized Absolute Error (MNAE) and variance of the estimated parameters. The optimized spin-lock time (TSL) schedules provided improved results over the non-optimized schedules for all cases that were tested. The simulations showed that optimized schedules can reach the same precision and reduce acquisition times by 16.5 min (42%) for the bi-exponential model, and 6.6 min (22%) for the stretched-exponential model. In t

SUBMITTER: de Moura HL 

PROVIDER: S-EPMC9546896 | biostudies-literature | 2022 Oct

REPOSITORIES: biostudies-literature