ASSESSMENT OF SKELETAL MATURATION IN INFANTS - COMPARISON BETWEEN 2 METHODS IN HYPOTHYROID PATIENTS

Background. Conventional skeletal radiography is the standard techniqu e for assessing skeletal age. However: radiography cannot demonstrate cartilage and is therefore of lesser value in infancy when the ossific ation centres are composed mainly of cartilage. By comparison, US clea rly demonstrates cartilage and bone. Objective. In the present study: we compared radiography and sonography for the assessment of skeletal age in neonates and infants. Materials and methods. Because delayed sk eletal maturation is a feature of congenital hypothyroidism and assess ment of skeletal age is routinely performed in our centre, we studied 55 hypothyroid infants (aged 7-66 days). AP radiographs and sonograms, acquired using high frequency scanners, were obtained and dimensions of the distal femoral epiphyseal ossification centre (DFE) were compar ed. Results. Measurements of DFE by the two methods showed excellent c orrelation (R = 0.94. P = 0.0001). Radiographs did not demonstrate a D FE in 11 infants, and US did not show it in 6. In no infant did radiog raphy demonstrate DFE not: seen by US. Moreover, DFE dimensions on US were larger than those measured on radiographs. Infants with absent th yroid gland had a DFE significantly smaller than those infants with ec topic or normally placed glands (P < 0.001), on both radiographs and s onograms. Conclusion. Our data suggest that sonography is a valid alte rnative to standard radiography for the assessment of skeletal age in infants.