Comparison of manual and computer-assisted automatic measurements of wall thickness of the left ventricle in two-dimensional echocardiography

To investigate the clinical applicability of automatic analysis of wall thickness in two-dimensional echocardiography, computer-assisted and conventional manual methods were compared in 26 cases. An echo threshold was automatically set in short-axis echo images through a discriminatory variance analysis of the signal-to-noise ratio. A fixed standard was determined inside the left ventricle using the circle window method, which we developed previously. Two abrupt echo reflections were selected as candidate points for the borders, and an outward search was conducted in all directions from a fixed standard to separately delineate the endocardial and epicardial interfaces. Interpolation using a spline function was applied to these points to complete the border lines. Differentiation was also used to eliminate the anterior and posterior papillary muscles. Significant correlations of r=0.98 were found between the computer and manual assessments of the epicardial and endocardial intraluminal ventricular areas (p<0.01). A correlation of r=0.87 was also obtained for myocardial wall thickness as determined by the 2 methods (p<0.01). Variability of the reproducibility using the computer method was 0.22% for the epicardial area and 0.64% for the endocardial area. These results confirm that computer-aided automatic measurement of wall thickness is clinically applicable to two-dimensional echocardiography .