3D‐T1ρ quantitation of patellar cartilage at 3.0T

Abstract

Purpose To demonstrate the feasibility of three-dimensional (3D) T_1ρ-weighted imaging of human knee joint at 3.0T without exceeding the specific absorption rate (SAR) limits and the measurement of the baseline T_1ρ values of patellar cartilage and several muscles at the knee joint. Materials and Methods 3D gradient-echo sequence with a self-compensating spin-lock pulse cluster of 250 Hz power was used to acquire 3D-T_1ρ-weighted images of the knee joint of five healthy subjects. Global and regional analysis of patellar cartilage T_1ρ were performed. Furthermore, T_1ρ of several periarticular muscles were analyzed. Results The global average T_1ρ value of the patellar cartilage varied from 39 to 43 msec. The regional average T_1ρ values varied from 38 to 42 msec, and from 42 to 44 msec for medial and lateral facets, respectively. In vivo reproducibility of average T_1ρ of patellar cartilage was found to be 5% (coefficient of variation). Similarly, the global average T_1ρ values for biceps femoris, lateral gastrocnemius, medial gastrocnemius, and sartorius varied between 31–46, 29–49, 35–48, and 32–50 msec, respectively. Conclusion We demonstrated the feasibility of 3D-T_1ρ-weighted imaging of the knee joint at 3.0T without exceeding SAR limits. J. Magn. Reson. Imaging 2006.