Development of a musculoskeletal relaxometry phantom for T1, T2, and T1rho measurements

Motivation: There is not a commercially available musculoskeletal (MSK) relaxometry phantom. Goal(s): Develop a dedicated MSK relaxometry phantom for T1, T2, and T1rho measurement quality assurance. Approach: A cylindrical phantom with 12 vials containing modulated T1 and T2 samples was created, with an MR-visible thermometer for temperature tracking. Phantom stands were used for consistent positioning. MRI/NMR measurements were collected for longitudinal stability and temperature dependence. Results: MRI measurements were in good agreement between two vendors with CVs<3% and demonstrated longitudinal stability with CVs<3% over a 3-month period. NMR measurements showed clear changes in T1, T2, and T1rho with changing temperature. Impact: A stable MSK relaxometry phantom prototype was successfully developed and characterized, including changes with temperature. With harmonized measurement protocols, this phantom will facilitate the use of quantitative relaxometry MRI in large-scale multi-site multi-vendor trials.