Evaluation of Humeral Head Cartilage Using the Magnetic Resonance Imaging T1ρ Relaxation Time Mapping Technique: A Comparison between Young and Elderly Healthy People

Objective: To evaluate the difference in the age-related cartilage changes of the humeral head with T1ρ relaxation time mapping and assess the normal distribution of the proteoglycan content of the humeral head in healthy volunteers without any symptoms or structural disorders. Materials and Methods: Twenty male volunteers (10 young subjects, 10 elderly subjects) for each generation group (mean age, young subjects: 30.2 ± 2.3 years; elderly subjects: 62.6 ± 6.2 years) participated in this study. Spectral attenuated inversion recovery T2-weighted imaging and T1ρ relaxation time mapping were performed using 3.0-Tesla magnetic resonance imaging. Regions of interest were located on the humeral cartilage on oblique coronal images from the bone–tendon junction to the inferior articular surface and divided the surface of the humeral cartilage into 6 areas. The T1ρ values of each area of the humeral head were measured and compared between groups. Results: The total mean T1ρ values were 40.9 ± 5.3 and 40.5 ± 3.5 ms for young and elderly volunteers, respectively. Comparison between ages showed no significant differences in the T1ρ values between each corresponding area. The T1ρ values of the inferior area of the humeral head in both young and elderly volunteers were significantly higher than those of the superior area. Conclusion: No marked age-related differences in the T1ρ values of the humeral head were observed between young and elderly volunteers without any symptoms or structural disorders. However, the T1ρ values in the inferior area of the humeral head were increased compared with those in the superior area.