Quantitative tibial ultrasonometry versus radiographic phalangeal absorptiometry in a Caucasian pediatric population

There is a need for a reliable bone assessment technique in children. In th is study, we compare an existing technique used in children, radiographic a bsorptiometry (RA), with a relatively novel technique, quantitative tibial ultrasonometry (QUS). In a prospective cohort study, we enrolled 290 girls (mean age 12.7 years) and 273 boys (mean age 12.4 years). Radiographs of th e left hand and the left index finger were taken with an aluminium referenc e wedge within the field of exposure. Radiographic absorptiometry on the se cond middle phalanx at the mid-level (BMD50%) and proximal quarter (BMD25%) was performed with interactive software. Tibial QUS was performed using th e SoundScan (R) Compact. Multiple regression analysis showed that SOS corre lated significantly with BMD25% for both boys (r = 0.65, P < 0.001) and gir ls (r = 0.59, P < 0.001), taking into account age and gender. The same appl ied for the correlation between speed of sound (SOS) and BMD50% in boys (r = 0.62, P < 0.001) and girls (r = 0.67, P < 0.001), Cubic regression betwee n calendar age and BMD25% showed the best fit for both boys (r(2) = 0.60) a nd girls (r(2) = 0.60). For BMD50% a difference in regression was found bet ween boys and girls. Quadratic regression gave a satisfactory fit for boys (r(2) = 0.61) whereas for girls, a cubic relation was best (r(2) = 0.59). O verall, there was a significant correlation between BMD25% and BMD50% for b oys r = 0.89 and for girls r = 0.91 (both P < 0.001). Our data show a signi ficant correlation between two different bone assessment techniques. In add ition, these data suggest that both tibial ultrasonometry and RA are useful techniques in children.