Measurement of end diastolic shape deformity using bending energy

An approach to analyzing the shape of the end-diastolic contour of the left ventricle of the heart is described. The procedure is adaptable to contour data derived from any one of several imaging modalities. The method involves modeling the contour as a thin flexible rod whose undeformed state is derived from measurements made on a group of normal patients. The amount of effort required to deform any particular contour away from the normal state into its characteristic shape is determined by first finding the local curvature differences between the contour and the mean normal contour at each of 100 normalized points. The weighted square of these differences, summed over all the points or some subset of them, is shown to be the global or regional bending energy of the contour. Resampling, smoothing and curvature-computation issues are considered for contours from contrast ventriculography and equilibrium radionuclide angiocardiography. Initial results show distinct bending-energy signatures for normal and abnormal studies and indicate the complimentary relationship between regional wall motion and regional bending-energy measurements.