ORIGINAL ARTICLES Automated Assessment of Ventricular Volume and Function by Echocardiography: Validation of Automated Border Detection Richard L. Morrissey, MD, Samuel C. Siu, MD,]. Luis Guerrero, BS, John B. Newell, BS, Arthur E. Weyman, MD, and Michael H. Picard, MD, Boston, Massachusetts To determine the utility of a new on-line echocardiographic automated border detection (ABD) algorithm in assessing ventricular volume and ejection fraction, an optimal model was studied. This open-chest canine model allowed continuous measurement of actual left ventricular volume. In four dogs, true end-systolic and end-diastolic volume and ejection fraction were compared with those obtained by two-dimensional echocardiography with an automated method calculated from a border detection algorithm to define left ventricular endocardium and the single-plane Simpson method to calculate volume. Left ventricular volumes that used manual, off-line tracings of the left ventricle by two-dimensional echocardiograms and the single-plane Simpson method were compared. The automated echocardiographic volumes correlated with true volumes (y = 0.7x + 8.9; standard error of the estimate = 13.5 cc; r = 0.81). A significant mean underestimation of ll ± 15 cc was noted (p < 0.0001). Volumes obtained from the manual tracings of left ventricular endocardial contours also correlated well with true volumes (y = 0.89x + 4; standard error of the estimate = 6.7 cc; r = 0.96). However, the 3 ± 7 underestimation was significantly lower than the error of the ABD method (p = 0.00005). Both on-line ABD and off-line ejection fractions correlated well with true ejection fractions (r = 0.94 and 0.96, respectively). There was no statistically significant difference between the mean errors of the ABD or manually derived ejection fractions. In the setting of optimal left ventricular imaging, the on-line and rapid features of this automated method make it potentially useful for quickly obtaining left ventricular volumes and ejection fraction.(] AM Soc EcHOCARDIOGR 1994;7: 107-115.) Quantitation of left ventricular function is critical for many aspects of clinical decision making. 1-4 The two most widely used indexes of left ventricular func- tion are chamber volume and ejection fraction. Two- dimensional echocardiography provides dimensional and area measurements noninvasively that can be in- tegrated into a variety of geometric models to cal- culate these parameters. 5 However, until recently even the simplest methods for analysis of two-di- From the Cardiac Unit of the Massachusetts General Hospital and Harvard Medical School. Presented in part at the Forty-second Annual Scientific Session of the American College of Cardiology, Anaheim, California, March 17, 1993. mensional images were dependent on off-line review and measurement by the operator. Because of the time required to perform these tasks, the full quan- titative capabilities of echocardiography were not used routinely and it was not feasible to assess changes in ventricular volume and performance as they occurred. Recent technologic advances have made it possible to detect ventricular borders auto- matically from thresholded-integrated backscatter images. 6 This approach offers the potential for rapid, on-line calculation of cardiac areas and, through fur- ther computer processing, volumes and ejection frac- tion. 7 • 8 However, the accuracy of these measurements has yet to be fully determined. Reprint requests: Michael H. Picard, MD, Cardiac Ultrasound Laboratory, VBK 508, Massachusetts General Hospital, Fruit St., Boston, MA 02114. Copyright " 1994 by the American Society of Echocardiography. 0894-7317/94$3.00 + 0 27/1151939 The aim of this study was to assess the accuracy of left ventricular volumes and ejection fractions cal- culated by a new on-line echocardiographic method for automated detection of ventricular borders. The optimal experimental setting was chosen to deter- 107