Evaluation of practical use of bone age assessments based on DXA-derived hand scans in diagnosis of skeletal status in healthy and diseased children.

The assessment of bone age is an important factor for the analysis of skeletal maturity, growth, and its aberrations. The classical method of bone age estimations is based on the recognition of changes in the radiographic appearance of the maturity indicators in hand-wrist radiographs by comparison with reference atlas. To apply bone age assessments, based on dual-energy X-ray absorptiometry (DXA)-derived hand scans, in the evaluation of skeletal status, 151 healthy children (4-18 yr old) and 61 with bone disorders (5-20 yr old) were investigated. All measurements were performed using Expert-XL and DPX-L densitometers (GE Lunar). Hand densitometry performed by the Expert-XL machine was used for the evaluation of bone age. Total-body measurements were performed using DPXL to calculate total-body bone mineral density (BMD) Z-score values as standard diagnostic parameters in pediatric densitometry and to verify diagnosis by taking into account assessed bone age. Strong correlations were found between BMD (g/cm2) and bone age in healthy children of both genders. We noted in several cases that low values of Z-scores (<-1) corresponded to delayed bone age in comparison to chronological age. After recalculation of BMD data according to bone age, a marked increase in Z-scores was noted, mainly in multihormonal pituitary-deficient subjects. It can be concluded that the use of hand densitometry in parallel with BMD measurements provide valuable information about skeletal maturation that leads to the improved diagnosis of skeletal status, especially in subjects with constitutional delay in growth.