Left Ventricle Longitudinal Axis Fitting and its Apex Estimation using a Robust Algorithm and its Performance: A Parametric Apex Model

For complete automatic left ventricle border detection in a cardiac frame, the apex needs to be located..4s the apex zone has less contrast and is harder to identify [l], [4] in the gray scale left ventriculograms, we use the left ven-tricle’s longitudinal axis [2] to assist in apex location. To automatically find the longitudinal axis of the left ventricle in any frame, we find the longest segment from either the anterior aspect of aortic valve or the inferior aspect of the aortic valve to the left ventricle border. We assume that the ruled surface generated by the sequence of longitudinal axes through the cardiac cycle is of sufficiently simple form, so that the perturbation error, especially the large errors, between the automatically measured axis and the physzcian defined axis can, in part, be filtered out by a robust proce