[Acoustic quantification--a new online procedure for automatic recording of left ventricular areas and area changes...

Initial experiences were obtained with a new technique for automatic quantification of left ventricular areas and area changes in two-dimensional (2D) echocardiograms (acoustic quantification, AQ). AQ is based on integrated back-scatter-analysis in real-time. Practicality and reliability of AQ were studied in 50 non-selected patients. AQ measurements of left-ventricular (LV) cavities were compared with off-line measurements which were obtained by analysis of videotaped images. Thirty-two (64%) and 39 (78%) patients could be studied by AQ from parasternal and apical views, respectively. LV areas measured from parasternal views or apical views showed a good correlation with corresponding values obtained by off-line analysis (r = 0.78 to 0.91). In addition, LV fractional area changes measured by AQ showed an excellent correlation with off-line measurements (parasternal: r = 0.86; apical: r = 0.84). During infusion of dobutamine (n = 3; 5, 10, 20 micrograms/kg/min, 10 min each dose), reduction of LV cavity areas could be continuously monitored and quantified by AQ for each cardiac cycle. In five of six patients who underwent transesophageal echocardiography, AQ could easily detect LV contours in the transgastric short axis view. Although AQ is not practicable in all patients, this new technique appears to be a promising and reliable approach for real-time, automatic boundary detection in 2D echocardiograms.