1. A method for predicting a post-stenting hemodynamic metric for a coronary artery stenosis from pre-stenting medical image data, comprising: extracting a pre-stenting patient-specific anatomical model of the coronary arteries from medical image data of a patient; simulating blood flow in the pre-stenting patient-specific anatomical model of the coronary arteries with a modified pressure-drop model for computing a pressure drop over a target stenosis region in the pre-stenting patient-specific anatomical model of the coronary arteries, wherein the modified pressure-drop model simulates an effect of stenting on the target stenosis region; and calculating a predicted post-stenting hemodynamic metric for the target stenosis region based on the pressure-drop over the target stenosis region computed using the modified pressure-drop model.