The usefulness of phalangeal quantitative ultrasound in the assessment of skeletal status in children and adolescents

Although dual energy x-ray absorptiometry (DXA) is the method considered to be the gold standard in pediatrics we must keep the disadvantages of this method in mind while trying to develop other more effective diagnostic tools for use in the pediatric population. In recent years, the method of quantitative ultrasound (QUS) has been developed for assessing bone properties. Low-frequency ultrasound travels across bone with a velocity that is related to bone quality and density. Furthermore, QUS techniques may be less influenced by bone size and can reveal physical properties of bone determined by bone composition and by structure. QUS is also void of ionizing radiation, cost-effective, portable and easy to use features which are beneficial in pediatrics. QUS systems exist for measurements at various skeletal sites such as calcaneous, phalanges, tibia and patella. Phalangeal QUS measurements have shown the ability to reveal changes due to skeletal growth, aging, and diseases. Large child and adolescent populations were measured and trends of changes in the measured ultrasound parameter during childhood and puberty were comparable with those shown in studies using DXA measurements. In case-control studies QUS proved its utility in the detection of skeletal changes in subjects with genetic disorders, renal osteodystrophy, acute lymphoblastic leukemia and in subjects treated with gonadotrophin-releasing hormone. There are also some longitudinal studies; in healthy children and adolescents and in survivors of malignant bone tumors and acute lymphoblastic leukemia, in subjects with renal insufficiency and in subjects with genetic disorders. Recently, phalangeal QUS and DXA measurements were compared in healthy subjects and have shown that QUS has the potential to express bone changes in measurements comparable to DXA.