Accurate quantification of mitral valve regurgitation (MR) is a challenging task in clinical cardiology. In order to develop and refine new algorithms for estimating the severity of MR using real-time 3D Doppler echocardiography (RT3DE), an experimental and numerical flow model have been designed and constructed. Using CAD, Rapid Prototyping Manufacturing (RPM) and five-axis milling technology, a hydraulic in vitro flow model, compatible for flow investigation with 2D normal speed Particle Image Velocimetry (PIV) and 2D Doppler Echocardiography. The same CAD model was used to conduct the Computational Fluid Dynamics (CFD) analysis. PIV, 2D Doppler Echocardiography and CFD results compare successfully in the upstream converging region and in the downstream turbulent regurgitated jet zone. These results are expected to improve the clinical assessment of mitral valve regurgitation severity by means of Doppler echocardiography.