A semi-automated edge detection method for the delineation of the endo- and epicardial borders of the left ventricle from cine MR images has been developed. The feasibility of this was demonstrated by processing end diastolic and end systolic ECG-gated images of four short axis images in 10 healthy subjects. The first derivative method combined with a 2D weighted polynomial fitting procedure was used to determine the endo- and epicardial borders, which then allowed determination of the wall motion, wall thickening, and ejection fraction, of the left ventricle. The results show that the end-systolic radial wall motion varies from (32+/-8)% to (76+/-12)%, and wall thickening from (0.60+/-0.46) cm to (1.26+/-0.50) cm. An average ejection fraction of (69+/-6)% was found which agrees well with literature values. The method described, for the delineation of the borders, reduces considerably the long and tedious operator time inherent in manual measurement and greatly increases the reproducibility of the measurements.