1. A method for determining fractional flow reserve (FFR) for a stenosis of interest for a patient, comprising: receiving medical image data of the patient including the stenosis of interest; extracting a set of anatomical and/or geometric features for the stenosis of interest from the medical image data of the patient; receiving a set of training data comprising: (1) measured FFR values and (2) anatomical and/or geometric features, of a plurality of individuals; training a machine learning algorithm based on determined associations mapping the measured FFR values and the anatomical and/or geometric features, for each of the plurality of individuals; determining a FFR value for the stenosis of interest based on the extracted set of anatomical and/or geometric features using the trained machine-learning algorithm mapping anatomical and/or geometric features to FFR values; and generating and displaying a geometric model of at least the stenosis of interest of the patient, and indicating the determined FFR value for the stenosis of interest in the geometric model.