Bone Age Assessment with Conventional Ultrasonography in Healthy Infants from 1 to 24 Months of Age

Background: Radiographic bone age determination is part of the routine evaluation of suspected growth disorders. Simplicity and low cost are its major advantages, but although the effective dose of ionizing radiation is low, it should be taken into consideration given its cumulative effect.

Objectives: To assess the chronological ultrasonographic emergence of the ossification centers of the hand and wrist.

Materials And Methods: Cross-sectional study of healthy patients ages 1 to 24 months (n=498) from Buenos Aires, Argentina. All patients underwent ultrasonographic evaluation of the left hand and wrist to identify the different bone nuclei; a subgroup of infants had their nuclei measured (n=228).

Results: Girls showed an earlier emergence of the evaluated nuclei and a trend to a greater size than age-matched boys. Size-for-age relation showed linear increase. Carpal bones (capitate and hamate) were the first to appear, as early as from the first 3 months of life, an age gap not thoroughly present on the radiographic atlas developed by Greulich and Pyle. The distal epiphysis of the radius and the second metacarpophalangeal joint (index finger) followed in order of emergence. The proximal epiphysis of the first metacarpal bone (thumb) was the last to emerge and was infrequently found on boys at age 24 months. Overall, these findings are in accordance with the radiographic atlas. An ultrasonography atlas of the left hand and wrist was outlined for girls and boys.

Conclusion: Conventional ultrasonography allows proper identification of the ossification centers of the hand and wrist and may become an innocuous follow-up tool for patients with growth disorders.