A Tracking System for Pulsed Ultrasound Images: Application to Quantification of Fetal Breathing Movements

A tracking system for quantification of moving structures from a real-time B-scan ultrasound image is described. The system provides a hard copy tracing of the movements with a resolution that is uncoupled from the wavelength of the ultrasound frequency employed. In the present instrument, a laboratory resolution of 0.06 mm and a differential target velocity of 961 mm/s has been achieved which has been more than adequate for tracking and recording all observed fetal movements, including the relatively high speed fetal hiccough. Both mechanical target tests and in vivo fetal breathing movements associated with maternal glucose loading are reported herein.