A medical diagnostic system includes an image processor to generate a differential frame from two consecutive medical images of the heart based on difference in pixel-by-pixel brightness of the consecutive images. A brightness segmentation image having a plurality of brightness zones is generated based of the differential frame. From the brightness zones, a turbulence index is calculated based on the iso-contour and the area in each brightness zone. The turbulence index is a quantitative representation of a degree of turbulence in the blood flow which can be used to generate a prognosis and/or diagnosis of cardiac function.
