Computer implemented method for quantitative flow analysis of a tree of conduits perfusing an organ from at least two bi-dimensional images of the tree or part of the tree obtained from different perspectives by an angiographic system, the method comprising the following steps: a) making a 3D reconstruction of at least part of the tree from said at least two bi-dimensional images; b) identifying a segment of interest within the 3D reconstruction semi-automatically upon user input; c) making calculations based on the 3D reconstruction to determine geometrical features of the conduits such as diameters, lengths, curvatures, centrelines or the like; d) receiving indication from the user on the heart type to retrieve from a storage unit or select from any available data source a functional model of the tree to be considered for the flow analysis and to input the location of the segment of interest within such model, wherein the functional model consists of a 1D model and a 0D model, wherein the 1D model comprises multiple segments identifying the conduits forming the tree with end parts connected with the 0D model to take the boundary conditions into account, wherein the 1D model includes information on generalized diameter, length and spatial orientation of the skeleton of each segment within the tree and the 0D model comprises lumped parameters using a hydraulic-electrical analogue; e) using the geometric features extracted from the 3D reconstruction to elaborate pressure equations of the functional model; f) adjusting the part of the functional model related to the segment of interest using geometrical features of the 3D reconstruction by fitting an equation for the segment of interest that calculates a pressure drop for a given flow value to reduce computation time; g) performing quantitative flow analysis based on the functional model so obtained which is displayed for the user. a) making a 3D reconstruction of at least part of the tree from said at least two bi-dimensional images; b) identifying a segment of interest within the 3D reconstruction semi-automatically upon user input; c) making calculations based on the 3D reconstruction to determine geometrical features of the conduits such as diameters, lengths, curvatures, centrelines or the like; d) receiving indication from the user on the heart type to retrieve from a storage unit or select from any available data source a functional model of the tree to be considered for the flow analysis and to input the location of the segment of interest within such model, wherein the functional model consists of a 1D model and a 0D model, wherein the 1D model comprises multiple segments identifying the conduits forming the tree with end parts connected with the 0D model to take the boundary conditions into account, wherein the 1D model includes information on generalized diameter, length and spatial orientation of the skeleton of each segment within the tree and the 0D model comprises lumped parameters using a hydraulic-electrical analogue; e) using the geometric features extracted from the 3D reconstruction to elaborate pressure equations of the functional model; f) adjusting the part of the functional model related to the segment of interest using geometrical features of the 3D reconstruction by fitting an equation for the segment of interest that calculates a pressure drop for a given flow value to reduce computation time; g) performing quantitative flow analysis based on the functional model so obtained which is displayed for the user. <EOS>