Objective: To investigate the role of 3T-MRI in assessing musculoskeletal health in children and young people.
Design: Bone, muscle and bone marrow imaging was performed in 161 healthy participants with a median age of 15.0 yrs (range, 8.0, 30.0).
Methods: Detailed assessment of bone microarchitecture (CISS sequence, voxel size 0.2x0.2x0.4mm3), bone geometry (TSE sequence, voxel size 0.4x0.4x2mm3) and bone marrow (1H-MRS, PRESS sequence, single voxel size 20x20x20mm3), size and muscle adiposity (Dixon, voxel size 1.1x1.1x2mm3).
Results: There was an inverse association of apparent bone volume/total volume (appBV/TV) with age (r, -0.5, p<0.0005). Cortical area, endosteal and periosteal circumferences and muscle cross-sectional area showed a positive association to age (r >0.49, p<0.0001). In those over 17 yrs of age, these parameters were also higher in males than females (p<0.05). This sex difference was also evident for appBV/TV and bone marrow adiposity (BMA) in the older participants (p<0.05). AppBV/TV showed a negative correlation with BMA (r, -0.22, p=0.01) which also showed an association with muscle adiposity (r, 0.24, p=0.04). Cortical geometric parameters were highly correlated with muscle area (r >0.57, p<0.01).
Conclusions: In addition to providing deep insight into the normal relationships between bone, fat and muscle in young people, these novel data emphasize the role of MRI as a non-invasive method for performing a comprehensive and integrated assessment of musculoskeletal health in the growing skeleton.