Bone ultrasound backscatter in the detection of bone nutritional status in term infants

Abstract

Objective To establish a reference range of cancellous bone ultrasonic backscatter coefficient (BSC) in term neonates, and to determine the significance of BSC in bone nutritional status in term newborns and infants. Methods Six hundred and sixty-five term newborns, who were born in Shanghai First Maternity and Infant Hospital from July 2014 to August 2014, were enrolled. On the third day and the 42nd day after birth, all infants underwent ultrasonic measurement of the calcaneum bone using a broadband–non-focus ultrasonic transducer at three frequencies (2.25, 3.5 and 5 MHz). MATLAB software was used to analyze the backscatter signals. Clinical data of the infants, including gestational age, birth weight and birth age, were recorded at the same time. Statistical analyses of the data included variance analysis, Tukey's test, rank sum test, Dunn test and Pearson or Spearman correlation analysis. Results (1) Of the 665 infants, 335 were male. The mean gestational age at birth was (38.0±1.9) weeks, and the mean birth weight was (3 152±226) g. (2) On the third day, there were significant differences in BSC values acquired at 2.25 and 3.5 MHz among the groups with different gestational ages or birth weights (2.25 MHz: H=9.842 and 17.271; 3.5 MHz: H=6.275 and 21.450, respectively, all P<0.05). At 3.5 and 2.25 MHz, BSC values were positively correlated with gestational age (r=0.047 and 0.035, respectively, both P<0.05) and birth weight (r=0.125 and 0.186, both P<0.05). (3) On the 42nd day, significant differences in BSC were observed at each frequency among the groups with different gestational ages or birth weights (gestational age: H=76.832, 16.498 and 32.756; birth weight: H=70.014, 18.095 and 34.126; all P<0.01). Gestational age and birth weight were positively correlated with BSC value acquired at each frequency (r=0.397, 0.286 and 0.272 for gestational age, 0.451, 0.223 and 0.196 for birth weight; all P<0.01). Conclusions A preliminary BSC reference percentile in term-born infants is established. There are positive correlations between BSC value and newborn gestational age and birth weight at certain frequencies, which can reflect the status of the newborn's cancellous bone. Determination of BSC value should be performed during the follow-up period to assess the nutritional status of neonatal bone. Key words: Bone density; Bone and bones; Ultrasonography; Infant, newborn; Nutritional satus