The strain at different locations in a subject's heart is determined by acquiring a series of MR images using a tagging pulse sequence (SPAMM) that produces a grid of lines in the reconstructed images. Circumferential strain, longitudinal strain, and the minimum principal strain angle, are all calculated at locations in the heart. These raw strain values are normalized by comparing them with corresponding values in a stored reference heart model. The normalized values at each location are combined to form a composite multiparametric strain index that is indicative of myocardial contractile function and these values are employed to modulate the color at corresponding locations in an anatomical image of the subject's heart.