An embodiment analyzes a body part of a patient, which patient is perfused with a contrast agent that is capable of circulating within the patient and of being substantially immobilized on a biological target. An embodiment of a corresponding system provides an echo signal that is indicative of a response over time to an interrogation signal of the body part, fits the echo signal with a time model function that models an evolution over time of the contrast agent in the body part, the time model function including a combination of a circulation function that models the circulation of the contrast agent and a decay function that models a decay of the echo signal from the immobilized contrast agent, and estimates at least one kinetics indicator of the contrast agent from the time model function.