The use of transmission ultrasonics to assess bone status in the human newborn.

The applicability of transmission ultrasonics as a method for assessment of bone status in human newborns was investigated in two studies. Sound transmission velocity (SCV) through the intact distal radius and ulna was compared to midshaft bone mineral content (BMC) and to midshaft mechanical breaking strength (MBS) in 13 postmortem newborns [gestational age (GA) = 20 to 41 wk]. Midshaft MBS, ranged from 1 to 16 kg; BMC, which ranged from 84 to 88 mg/cm in the term infant, was consistent with previous reported photon absorptiometric data. SCV in the distal radius and ulna was correlated with midshaft MBS (r = 0.69 to 0.82) and BMC (r = 0.85 to 0.93) and increased exponentially with midshaft MBS and BMC. GA was correlated with SCV (r = 0.90 to 0.95). Log GA was correlated with midshaft MBS (r = 0.87 to 0.96) and BMC (0.97 to 0.99) in each of the four measured bones. In the second study, SCV through the distal radius and ulna was measured in 85 live newborns ranging in GA from 28 to 43 wk. SCV increased linearly with GA (r = 0.71 to 0.77). These data demonstrate that SCV through the distal radius and ulna increases linearly with GA and that SCV through the distal bones of the forearm is reliably related to midshaft BMC and MBS during the third trimester of gestation. Transmission ultrasonic measurement of SCV provides a rapid, reproducible, nonionizing, and noninvasive method for assessing bone strength and mineralization in human neonates.