A method of determining the blood flow through coronary arteries comprises generating (S1) a 3D image data set of at least the coronary arteries and the myocardial muscle, generating (S2) a 3D marker data set of at least the myocardial muscle from a dual-energy or spectral 3D data set obtained after administration of a marker, said 3D marker data set indicating the amount of said marker contained within voxels of said myocardial muscle, subdividing (S3) the myocardial muscle into myocardial muscle segments, determining (S4) which coronary artery supplies the respective myocardial muscle segments, determining (S5) the volume of blood that flows into the respective myocardial muscle segments from said 3D marker data set, and determining (S6) the total volume of blood that flows into a coronary artery of interest by summing the volume of blood flowing into all myocardial muscle segments supplied by said coronary artery.
