The invention relate to a system and a process for estimating hemodynamic parameters by applying soft probabilistic methods to perfusion imaging. Such a process also makes it possible to estimate arterial input or complementary distribution functions and therefore more generally any quantity of interest. The invention stands out in particular from the known processes in that it requires the introduction, a priori, of soft information of physiological or hemodynamic nature without constraining of forcing the desired estimation through arbitrary or undesirable hypotheses.