COMPUTERIZED QUANTITATIVE-ANALYSIS OF LEFT-VENTRICULAR WALL MOTION BY TWO-DIMENSIONAL ECHOCARDIOGRAPHY

Quantitative detection of left ventricular segmental wall motion abnormalities by any modality depends on the reference system used because of the dynamic geometry of contraction and cardiac motion within the thorax. To assess the feasibility and accuracy of quantitative analysis of left ventricular wall motion by 2-dimensional echocardiography. Subjects (61) were studied with the use of 44 different reference methods in each of 3 echocardiographic views: the parasternal short-axis view at the levels of the mitral valve and of the papillary muscles, and an apical 4-chamber view. The 3 major groups of reference systems used were those with a fixed external reference, a floating reference correcting for translation, and systems correcting for both translation and rotation. In the 1st part of this study the end-diastolic and end-systolic outlines of 20 normal subjects were stored in a computer and composite data of these 20 subjects were plotted to obtain a 95% confidence interval for measured normal fractional change for each reference method. In the 2nd part of the project an additional prospective group of 10 normal subjects and a group of 31 abnormal patients had their left ventricular wall motion analyzed by similiar methods, and the results were compared with all the confidence intervals. One reference method was selected for each 2-dimensional echocardiographic view based on the highest sensitivity and specificity found by statistical analysis; a floating-reference system including translation was found to be optimal for the apical 4-chamber and parasternal short-axis views at the level of the mitral valve, and a fixed external reference system was optimal for the short-axis view at the papillary level. The percent fractional shortening of radial dimensions (radial methods) and the percent fractional change in area measurements (area methods) during the cardiac cycle were also calculated at 5.degree., 10.degree., 20.degree., 30.degree. and 45.degree. intervals around the outline perimeter for each subject according to each of the 44 different methods. Area methods yielded the same specificity and sensitivity as radial dimension analysis methods at 5.degree.-45.degree. intervals. Ten normal subjects underwent repeat echocardiography within 2 days of their 1st study to examine day-to-day variation. Average change in mean contraction from day to day was 7-9% for radial methods and 9-13% for area methods. A computerized system for unbiased selection of optimal methods of analysis of left ventricular wall motion by 2-dimensional echocardiography is presented. One reference method that had the optimal sensitivity and specificity was selected among 44 different methods for each echocardiographic view. Reproducibility was good for the group as a whole but in individual cases there is significant variation from day to day. Radial methods were not appreciably different from area methods with respect to sensitivity, specificity or reproducibility, or with increasing subdivision of the endocardial contour.