Monitoring bone growth using DXA and pQCT

Abstract

The structure and strength of bone established at the cessation of growth have strong influence on the emergence of skeletal fragility later in life. Monitoring bone growth and timely intervention to avoid long-term consequence of diseases or medications on bone health becomes an indispensable part of paediatric patient care. However, the tools available for assessment of bone mineral density (BMD) and structure in children are limited and most of these tools were developed for and thus limited their use to adults (e.g. DXA). Bone is a 3D structure composed of cortical and trabecular bone varying in proportion from bone to bone and from site to site along a bone. Understanding the effects of diseases or medications on bone development thus requires precise measurement of the 3D bone structure which cannot be fulfilled by 2D imaging techniques. The quantitative computed tomography (QCT), especially the high-resolution peripheral QCT (HRpQCT), is becoming a necessary tool for paediatric patients due to its capacity to assess bone structure and thus strength. This chapter will address the use of the two commonly used techniques in children, focusing on their indications and interpretation.