Ultrasonic Doppler techniques have been developed for the detection
of uterine blood flow. The work was undertaken to provide a noninvasive method for the study of foetal haemodynamics.
The operation of the continuous wave and the pulsed wave Doppler
instruments and the factors which influence their performance are discussed. The different types of Doppler signal extraction
techniques which can be used with the pulsed wave Doppler are described. A design for a 2.5 MHz pulsed wave Doppler instrument
is presented. The results of in vivo and in vitro trials with
this instrument are presented.
A blood flow instrument specially designed for examining blood flow
in the pregnant uterus is described. It consists of a real time
ultrasonic scanner of rotating transducer design used in conjunction
with the above types of Doppler instrument. In vivo evaluation of
this equipment is presented.
A novel type of continuous wave Doppler instrument, the intersecting
zone Doppler is described. This device overcomes the problem of
lack of localisation normally associated with the continuous wave
A composite blood flow system incorporating all three Doppler
techniques is described. Blood flow spectrograms from various sites
within the pregnant uterus are presented.