Evaluation of left ventricular ejection function by an automatic Doppler signal quantification system

In the present study, an automatic quantification program was developed for flow tracing from Doppler flow images. Five important parameters, (1)ejection period (EP), (2) ratio of one-third-time ejected volume and ejected volume (1/3EV:EV), (3) ratio of two-third-time ejected volume and ejected volume (2/3EV:EV), (4) averaged flow acceleration during increasing flow duration (AFA) and (5) peak flow acceleration (PFA) were calculated from the traced flow. Six normal volunteers (mean age 23.5 years) were included in this study. They were studied using continuous wave Doppler echocardiography and during a controlled venous injection of dobutamine. From normal steady state, six stages were performed, each stage has approximate five minutes with injection rate increment of 2.5 μg /kg/min. The results show that the 1/3EV:EV and 2/3EV:EV varied in a very small range. On average, PFA increased from 7.1905 m/sec² to 25.0498 m/sec² and average AFA increased from 4.9501 m/sec² to 16.1201 m/sec². It was concluded that based on the benefit of reproducibility and efficiency of Doppler flow image measurement, our image quantification system not only benefits daily diagnostic usage but also provides a reliable data analysis for left ventricular contractility evaluation.