The invention concerns a system and method for reconstructing a physiological signal of an artery/tissue/vein system of an organ in a surface space. Said method is implemented by processing means of a processing unit of a functional imaging analysis system, and comprises a step for reconstructing said physiological signal from a piece of experimental data of a region of interest comprising an elementary volume—called a voxel—of said organ and a surface mesh describing said surface space. The invention differs from known methods in particular in terms of the high accuracy of same and the robustness thereof to noise.