A new technique for improved diagnosis of local placental abnormalities: Fourier analysis of intraplacental waveforms.

A new method to diagnose localized placental lesions is introduced. The method involves Fourier analysis of intraplacental and umbilical Doppler velocity waveforms. It is shown, using a theoretical model based on an electrical transmission line approach, that intraplacental waveforms that are of higher pulsatilities than those in the umbilical artery indicate placental abnormalities. The method was applied in a series of cases with normal umbilical waveforms in which placental abnormalities were diagnosed. The method promises to be more sensitive and specific than analyzing umbilical waveforms alone as it does not depend on uncertain threshold values.