A medical image processing method of determining a fractional flow reserve through a stenosis of a coronary artery from medical image data is disclosed. The medical image data comprises a set of images of a coronary region of a patient. The coronary region includes the stenosis. The method comprises: reconstructing a three dimensional model of a coronary artery tree of the patient from the medical image data； determining stenosis dimensions from the three dimensional model of the coronary artery tree of the patient； simulating blood flow in the three dimensional model of the coronary artery tree of the patient to determine modeled flow rates； using an analytical model depending on the stenosis dimensions to predict a modeled pressure drop over the stenosis from the modeled flow rates； and determining the fractional flow reserve through the stenosis from the modeled pressure drop.
