1Department of Medical Engineering and Systems Cardiology, Kawasaki Medical School, 2Tenri Hospital, 3Osaka Prefectural Hospital, 4National Cardiovascular Center
Coronary, High resolution, Velocity profile, Fourier transform, Disturbance
Multigated high frequency (20 MHz) pulsed Doppler velocimeter was developed to measure the detailed blood velocity profile in a relatively small artery, especially in a coronary artery during open chest surgical operation. Maximum depth for measurements of the velocimeter was 15 mm. Velocity measurements at 50 sampling points were performed by multigated zerocross method. This made it possible to evaluate a detailed blood velocity profile across a vessel in real time. Our velocimeter has a channel for real time discrete Fourier transform to evaluate a spread of velocity distribution in the sample volume. A suction cup type probe was developed to measure blood velocities in epicardial coronary vessels without stripping off the coronary artery. Detailed blood velocity profiles in human left coronary artery was obtained successfully by our method during open chest surgery. It was also shown that FFT was useful for the evaluation of flow disturbances, as seen in the case with coronary artery stenosis.