  Examination of the umbilical artery with Doppler ultrasonography is performed
to investigate blood supply to the fetus through the umbilical cord, which is
vital for the monitoring of fetal health. Such examination involves several
steps that must be performed correctly: identifying suitable sites on the
umbilical artery for the measurement, acquiring the blood flow curve in the
form of a Doppler spectrum, and ensuring compliance to a set of quality
standards. These steps rely heavily on the operator's skill, and the shortage
of experienced sonographers has thus created a demand for machine assistance.
In this work, we propose an automatic system to fill the gap. By using a
modified Faster R-CNN network, we obtain an algorithm that can suggest
locations suitable for Doppler measurement. Meanwhile, we have also developed a
method for assessment of the Doppler spectrum's quality. The proposed system is
validated on 657 images from a national ultrasound screening database, with
results demonstrating its potential as a guidance system.
