[Echocardiographic on-line volumetry using acoustic quantification--comparison with manual echocardiographic analysis...

Acoustic quantification (AQ) represents an ultrasound imaging system which provides detection and tracking of endocardial blood boundaries based on quantitative assessment of acoustic properties of tissue in real time. To assess on-line quantitation of left ventricular enddiastolic (EDV), endsystolic (ESV) volumes and ejection fractions (EF) AQ measurements were compared with off-line measurements obtained by manual analysis of video-taped images (MAN) and with cineventriculographic data (CV). Calculations by the AQ system were based on an algorithm using the monoplane disc method. One day before undergoing CV, 88 unselected patients were studied with echocardiography in the apical four-chamber view. Seventy (79.5%) patients could be studied by AQ. The regression equations for determination of EDV were y = 0.7x + 25.2; r = 0.87 (AQ vs. MAN) and y = 0.5x + 22.8; r = 0.80 (AQ vs. CV), for determination of ESV they were y = 0.8x + 11.4; r = 0.78 (AQ vs. MAN) and y = 0.7x + 6.9; r = 0.71 (AQ vs. CV), and for determination of EF they were y = 0.7x + 9.5; r = 0.77 (AQ vs. MAN) and y = 0.6x + 15.0; r = 0.71 (AQ vs. CV). Calculations of left ventricular volumes by AQ or MAN led to a systematic underestimation, compared to CV. EF was also underestimated by AQ, whereas no significant difference between the mean values of MAN and CV exists. In a heterogenous population, acoustic quantification based on quantitative assessment of tissue acoustic properties mostly permits on-line quantitation of left ventricular volumes and ejection fractions in real-time.