A method of ultrafast imaging, the method comprising: transmitting a plurality of ultrasound pulses toward a medium from a transducer array, wherein the plurality of ultrasound pulses includes a regularly repeated sequence comprising a Doppler burst (10-1', 10-2', 10-3') of M unfocused first pulses and a B-mode burst (11, 15) of N second pulses, where M is 2 or more and N is 1 or more, and wherein the plurality of ultrasound pulses includes multiple repetitions of the sequence; wherein the M first pulses in each Doppler burst are transmitted within an intra-sample time interval which is less than one eighth of the wavelength of the unfocused pulses divided by a maximum expected axial velocity of the medium, wherein successive Doppler bursts are temporally spaced by an inter-sample time interval which is less than one quarter of their wavelength divided by the maximum expected axial velocity of the medium, detecting echoes responsive to the transmitted plurality of ultrasound pulses, wherein the detecting includes: detecting, within a field of view, FOV, of the array, first sets of echoes, each first set of echoes being responsive to a respective unfocused first pulse in a Doppler burst, wherein the first sets of echoes include all detected echoes of at least one Doppler burst, and detecting a B-mode image frame comprising the echoes of multiple B-mode bursts of the multiple repetitions of the sequence; generating a Doppler sample from the first sets of echoes; generating Doppler image data from the Doppler sample; generating B-mode image data from signals representative of the B-mode image frame; and simultaneously displaying the Doppler image data and the B-mode image data; wherein the echoes from more than M successive first pulses are used simultaneously to generate each Doppler sample, so that the first sets of echoes used to generate each Doppler sample include the echoes from two or more successive Doppler bursts. transmitting a plurality of ultrasound pulses toward a medium from a transducer array, wherein the plurality of ultrasound pulses includes a regularly repeated sequence comprising a Doppler burst (10-1', 10-2', 10-3') of M unfocused first pulses and a B-mode burst (11, 15) of N second pulses, where M is 2 or more and N is 1 or more, and wherein the plurality of ultrasound pulses includes multiple repetitions of the sequence; wherein the M first pulses in each Doppler burst are transmitted within an intra-sample time interval which is less than one eighth of the wavelength of the unfocused pulses divided by a maximum expected axial velocity of the medium, wherein successive Doppler bursts are temporally spaced by an inter-sample time interval which is less than one quarter of their wavelength divided by the maximum expected axial velocity of the medium, detecting echoes responsive to the transmitted plurality of ultrasound pulses, wherein the detecting includes: detecting, within a field of view, FOV, of the array, first sets of echoes, each first set of echoes being responsive to a respective unfocused first pulse in a Doppler burst, wherein the first sets of echoes include all detected echoes of at least one Doppler burst, and detecting a B-mode image frame comprising the echoes of multiple B-mode bursts of the multiple repetitions of the sequence; detecting, within a field of view, FOV, of the array, first sets of echoes, each first set of echoes being responsive to a respective unfocused first pulse in a Doppler burst, wherein the first sets of echoes include all detected echoes of at least one Doppler burst, and detecting a B-mode image frame comprising the echoes of multiple B-mode bursts of the multiple repetitions of the sequence; generating a Doppler sample from the first sets of echoes; generating Doppler image data from the Doppler sample; generating B-mode image data from signals representative of the B-mode image frame; and simultaneously displaying the Doppler image data and the B-mode image data; wherein the echoes from more than M successive first pulses are used simultaneously to generate each Doppler sample, so that the first sets of echoes used to generate each Doppler sample include the echoes from two or more successive Doppler bursts.