EVALUATION OF BONE-DENSITY IN NEWBORN-INFANTS BY COMPUTED X-RAY DENSITOMETRY

We evaluated bone density in term and preterm infants using computed x -ray densitometry, which permits measurement of bone density with mini mal disturbance to the infants in their incubators. Bone density, bone width, and bone length of the right radius were determined in 155 inf ants of appropriate weights for their gestational ages (23 to 41 weeks ). A curve for intrauterine bone growth was extrapolated from these da ta. The mean coefficients of variations for variabilities for intra- a nd interobserver error for all measurements were <3.5%. In 18 infants, measurements of the right forearm were obtained in two positions to c onfirm the validity of densitometric measurements. The mean coefficien ts of variation were 3.42% for bone density, 3.48% for bone width, and 0.21% for bone length. Bone density was significantly correlated with gestational age (r = 0.924) and birth weight (r = 0.921). Bone width and length were also correlated with gestational age (r = 0.866 and 0. 937) and birth weight (r = 0.878 and 0.954). Our results suggest that computed x-ray densitometry is a useful method for evaluation of bone density in preterm infants, including those in an intensive care envir onment.