An Imaging Gate Pulse Doppler for Examination of Coronary Bypass Graft Patency

Standard pulse echo and pulse Doppler ultrasonic instruments have been used with some success in examinations of the coronary circulation. The left main coronary artery was detected and stenosis at this site diagnosed using two-dimensional echocardiography. (1) Patency of aortocoronary bypass grafts was determined with some success using pulse Doppler. (2) Use of these techniques is difficult, however, so they have not become a common exam in normal clinical practice. The Imaging Gate Pulse Doppler (IGPD) was developed to be a tool which would improve the ability to noninvasively assess coronary and cardiac dynamics, by providing images of flow in vessels which are in the vicinity of strong stationary echos and low frequency motion signals arising from the heart walls.