1. A method for estimating one or more haemodynamic perfusion parameters of an elementary volume—referred to as a voxel—of an organ, said method being implemented by a processing unit of a perfusion imaging analysis system, and comprising a step for estimating one or more haemodynamic parameters from perfusion signals S(t), wherein the step for estimating the haemodynamic parameter or parameters includes a joint estimation of the parameters Θ of a global perfusion model comprising: a first relationship between the perfusion signal S(t) and a concentration C(t) of a contrast agent circulating in said voxel over a time t; a second relationship between the concentration C(t) of a contrast agent, the blood flow BF, a parametric or semiparametric model C a (t,Θ a ) of an arterial input function and a parametric or semiparametric model R(t,Θ R ) of a complementary cumulative distribution function of the transit time in the voxel, Θ a and Θ R being respectively the parameters of the models C a (t,Θ a ) and R(t,Θ R ).