Assessing the effects of spin lock time duration on T1ρ relaxation times for imaging of the articular cartilage in the knee

There is limited standardization of T1ρ acquisition parameters with respect to spin lock times (TSLs). Shorter TSL durations are susceptible to underestimating knee cartilage T1ρ relaxation times, warranting optimization for maximal measurement stability. Additionally, vertical estimation of T1ρ relaxation times throughout cartilage layers is limited. Here, we utilized 40 healthy knees to demonstrate enhanced T1ρ relaxation time measurement stability with maximum TSLs of 90 to 120ms compared to shorter TSL durations. Depth-specific differences in T1ρ were further compartmentalized into deep and superficial knee cartilage layers, highlighting the potential for T1ρ to indirectly and non-invasively evaluate proteoglycan content across cartilaginous layers.