A perfusion assessment system (105) is proposed. The system includes means (705-730) for providing an echo-power signal indicative of a reperfusion of a contrast agent in a body-part of a living subject following destruction of a significant portion of the contrast agent in the body-part, means (735-767) for associating the echo-power signal to a perfusion function with an S-shape based on a plurality of elementary perfusion functions with said S-shape each one for a corresponding value of at least one perfusion parameter, the elementary perfusion functions being weighted according to a probability density distribution of the at least one perfusion parameter, wherein the S- shape includes an initial portion with substantially zero first derivatives, a final portion with substantially zero first derivatives, and a central portion between the initial portion and the final portion changing monotonically from a value of the initial portion to a value of the final portion, means (770) for determining at least one shape indicator of the probability density distribution, and means (775-785) for comparing the at least one shape indicator with at least one predetermined further shape indicator to identify morphological characteristics of the body-part according to a result of the comparison.Linvention concerne un système dévaluation de perfusion (105). Le système comprend des moyens (705-730) destinés à fournir un signal de puissance écho, indicateur dune reperfusion dun agent de contraste dans une partie du corps dun sujet vivant, à la suite dune destruction dune partie importante de lagent de contraste dans la partie du corps des moyens (735-767) permettant dassocier le signal de puissance écho à une fonction de perfusion de forme S, basée sur une pluralité de fonctions de perfusion élémentaire ayant ladite forme S, chacune delles ayant une valeur correspondante dau moins un paramètre de perfusion, les fonctions de perfusion élémentaires étant pondérées conformément à une
