Approximation of the left ventricle by a cone of revolution using biplane measurements

A new method based only on area measurements was developed for calculating left ventricular volume from biplane (RAO and LAO) left ventriculograms; the ventricle was approximated by a cone of revolution. Twenty-three patients with normal and 23 patients with abnormal left ventricles were studied. The Dodge method provided reference values. There was no significant difference between values for EDV calculated by either method; values for ESV calculated by the cone method were consistently higher, but the error is acceptable. The cone method provides results similar to those obtained by the corrected Dodge method, eliminating the problem of choosing and measuring the long axis.