  Current imaging techniques in echography rely on the pulse-echo (PE) paradigm
which provides a straight-forward access to the in-depth structure of tissues.
They inherently face two major challenges: the limitation of the pulse
repetition frequency, directly linked to the imaging framerate, and, due to the
emission scheme, their blindness to the phenomena that happen in the medium
during the majority of the acquisition time. To overcome these limitations, we
propose a new paradigm for ultrasound imaging, denoted by continuous emission
ultrasound imaging (CUEI) \cite{CEUIpatent2023}, for a single input single
output (SISO) device.
  A continuous insonification of the medium is done by the probe using a coded
waveform inspired from the radar and sonar literature. A framework coupling a
sliding window approach (SWA) and pulse compression methods processes the
recorded echoes to rebuild a motion-mode (M-mode) image from the medium with a
high temporal resolution compared to state-of-the-art ultrafast imaging
methods.
  A study on realistic simulated data, with regards to the motion of the
medium, has been carried out and, achieved results assess an unequivocal
improvement of the slow time frequency up to, at least, two orders of magnitude
compared to ultrafast US imaging methods. This enhancement leads, therefore, to
a ten times improvement in the temporal separability of the imaging system. In
addition, it demonstrates the capability of CEUI to catch relatively short and
quick events, in comparison to the imaging period of PE methods, at any instant
of the acquisition.
