LEFT-VENTRICULAR SHAPE-ANALYSIS FROM 3-DIMENSIONAL ECHOCARDIOGRAMS

The objective of this study was to develop and validate a three-dimens ional technique of left ventricular shape analysis. Geometric phantoms and left ventricles of excised calf hearts, normal human subjects, an d one subject each with aortic stenosis and dilated cardiomyopathy wer e reconstructed from three-dimensional echocardiograms. The fit betwee n the reconstructions and true surfaces of the geometric phantoms and excised ventricles was determined. To evaluate in vivo left ventricula r shape, a center axis was constructed from the centroid of the mitral annulus to the furthest endocardial point. Regional shape was evaluat ed as the relative distances of 16 separate myocardial segments from t he center axis compared with a population-derived mean value. Global s hape was evaluated as the average standard deviation from the normal v alue over the 16 segments. The system precisely reproduced the shapes of the phantoms and excised left ventricles (root-mean-square error be tween true and reconstructed surface 1.0 0.2 mm and 1.2 0.8 mm, respec tively). The in vivo shape analysis differentiated the pathological fr om normal left ventricles.