Doppler obstetric ultrasound: a graphical display of temporal changes in safety indices.

Abstract

To investigate ultrasound use and exposure in pregnant women undergoing Doppler ultrasound investigation of the maternal and fetal circulation using Doppler ultrasound techniques. Sample graphical displays were generated showing duration of each mode, thermal and mechanical index levels and overall elapsed time of scan and modes. The displays revealed combinations of scanner settings which delivered higher output intensity levels and which we subsequently altered in our practice to reduce ultrasound exposure. A display of this type would enable monitoring of output levels and exposures, especially for operators undergoing training in Doppler applications. It would also identify poor practice where there is prolonged exposure at high output levels. Such a display, in combination with accurate output measurement from manufacturers and independent laboratories, would help to ensure the safe use of ultrasound in fetal assessment.