Feasibility and reproducibility of relaxometry, morphometric. and geometrical measurements of the hip joint with magnetic resonance imaging at 3T

Purpose: To test the feasibility of in vivo magnetic resonance TIP relaxation time measurements of hip cartilage, and quantify the reproducibility of hip cartilage thickness, volume, T-2, TIP, and size of femoral head measurements. Materials and Methods: The hip joint of five human healthy volunteers, one subject with mild hip osteoarthritis (OA) and one subject with advanced hip OA, was imaged with magnetic resonance imaging (MRI) at 3T. Hip cartilage thickness, volume, TIP, and T2 were quantified, as well as the size of the femoral head. All imaging and analysis procedures were performed twice for the, healthy volunteers to assess reproducibility. Results: In vivo MR T-1p measurements of hip cartilage At 3T were feasible as demonstrated by high quality images and relaxation time maps. High levels of reproducibility were obtained for measurements of hip cartilage thickness (CVSD = 2.19%), volume (CVSD = 3.5%), T2 (CVSD = 5.89%), T1p (CVSD = 2.03%), and size of femoral head (CVSD 0.49%). Mean T-2 and T-1p relaxation time values for human I healthy subjects were.128.38 (+/- 2.66) msec and 38.72 (+/- 3.84) msec, respectively. Mean T2 and T, p relaxation time values for subjects with OA were 34.78 (+/- 8.36) msec and 44.07 (+/- 0.99) msec, respectively. T2 and TIP values increased from the deep to the superficial layers. Conclusion: Qualitative and quantitative results indicate that the MRI techniques presented in this study may be applied clinically to patients with OA of the hip to investigate these parameters at different stages of disease.