Fourier coefficient description of left ventricular shape

A method of quantifying the shape of the left ventricle of the heart as seen in 2D echocardiograms was developed. It is based on describing the shape in terms of the coefficients a fifth-order trigonometric Fourier series. Such a series has eleven Fourier coefficients which is too large a number for clinical application so pairs of coefficients are combined to give six coefficients (alpha 0, alpha 1, ... , alpha 5). A trial was conducted to test the ability of the coefficient description to classify subjects as having normal right ventricles or ventricles with an apical abnormality. The tests showed that one of the coefficients (alpha 2) was higher for the subjects with an apical abnormality and that this difference increased with exercise. This is as was expected. However, it was found to be difficult to get a reliable estimate of alpha 2 from a single scan of a patient and that it is therefore probably necessary to average data from several scans to obtain a reliable alpha 2 value for a single patient.