Assessment of left ventricular contraction by parametric analysis of main motion (PAMM): theory and application for echocardiography.

The computerized study of the regional contraction of the left ventricle has undergone numerous developments, particularly in relation to echocardiography. A new method, parametric analysis of main motion (PAMM), is proposed in order to synthesize the information contained in a cine loop of images in parametric images. PAMM determines, for the intensity variation time curves (IVTC) observed in each pixel, two amplitude coefficients characterizing the continuous component and the alternating component; the variable component is generated from a mother curve by introducing a time shift coefficient and a scale coefficient. Two approaches, a PAMM data driven and a PAMM model driven (simpler and faster), are proposed. On the basis of the four coefficients, an amplitude image and an image of mean contraction time are synthesized and interpreted by a cardiologist. In all cases, both PAMM methods allow better IVTC adjustment than the other methods of parametric imaging used in echocardiography. A preliminary database comprising 70 segments is scored and compared with the visual analysis, taken from a consensus of two expert interpreters. The levels of absolute and relative concordance are 79% and 97%. PAMM model driven is a promising method for the rapid detection of abnormalities in left ventricle contraction.