In the late-gestation fetal mouse, exposure to piezoelectric lithotripter fields at amplitudes < 1 MPa produced hemorrhages in tissues near developing bone, such as the head and limbs. This study was undertaken to determine if exposure to pulsed ultrasound at diagnostic frequencies produces similar hemorrhages in the late-gestation fetal mouse. On the 18th day of gestation, fetal mice were exposed in utero to pulsed ultrasound with a 10-μs pulse duration and 100-Hz pulse repetition frequency for a total exposure duration of 3 min. Hemorrhages occurred most often to the developing fetal head. At 1.2 MHz, a threshold for hemorrhage to the fetal head was determined at positive exposure pressures of ~ 4 MPa and corresponding negative pressures of ~2.5 MPa. The threshold increased with at least the first power of frequency. Copyright (C) 1999 World Federation for Ultrasound in Medicine and Biology.
- Pulsed ultrasound
ASJC Scopus subject areas
- Radiological and Ultrasound Technology
- Acoustics and Ultrasonics