Measurement of forearm bone in children by peripheral computed tomography

By means of peripheral computed tomography (pQCT), adult cortical bone density and volume was shown to be under a fixed rectilinear relationship regardless of age, sex, and presence or absence of osteoporosis. In children, however, the density-volume regression line followed a clearly different slope from that for adults (P < 0.001), indicating a difference in property and composition of the cortical bone between growing bone of children and grownup bone of adults. Although both relative cortical volume and density increased with age in both boys and girls, no significant increase of trabecular bone was noted in either during the growth period. When the same technique was applied to the bone of rats known to continue growing with indefinite modeling without remodeling, the regression line between cortical bone density and volume was different from that of adult humans and similar to that of growing human children. Growing bone in a constant process of modeling and mineralization thus seems to have cortical bone possibly with less complete mineralization somewhat different from those of grown-up bone only undergoing remodeling. Selective cortical bone measurement by pQCT appears to be useful in characterizing the unique properties of the cortex of the growing bone.