Ultrasound imaging method combined with the presence of contrast agents in the body under examination, comprising the steps of: transmitting at least one beam of acoustic waves into a body under examination carrying contrast agents, and which acoustic waves are transmitted at a first fundamental transmission frequency and are focused on at least one scan line receiving the acoustic beam reflected from the body under examination and the contrast agents along said at least one scan line separating, in said received signal, the at least one harmonic or subharmonic components from the fundamental frequency component generating one image from at least one of the fundamental, harmonic and/or subharmonic components of the received signal. According to the invention, the components of the received signal are separated according to their being at the first fundamental frequency, at the harmonic frequency and at the subharmonic frequency whereas the amplitudes of the received signals are stored for each of the fundamental, harmonic or subharmonic frequency components at each reflected point depending on the amplitudes of the signal components, the reflector nature is determined, said nature being assumed as a contrast agent, when the subharmonic component of the received signal has an amplitude above a predetermined minimum amplitude.
