Cancellation of Doppler intrinsic spectral broadening using ultrafast Doppler imaging

Although conventional pulse-wave Doppler has proved to be a valuable diagnostic method for many vascular pathologies, it is hampered by issues related to repeatability as well as problems associated with quantification and system-dependent variability. These limitations are due to intrinsic spectral broadening on the Doppler spectrum, resulting from the directivity pattern of the ultrasound focused beam. Here, we develop a new spatial statistical technique, Doppler frequency spatial analysis (DFSA), which is based on ultrafast plane-wave imaging. Similar to standard pulse-wave Doppler, which is commonly used by sonographers, it yields a two-dimensional output (frequency versus time), while dramatically reducing the presence of intrinsic spectral broadening on the Doppler spectra. Therefore, the technique is much more sensitive to the velocity profile and turbulences than the standard pulse-wave Doppler. The proposed technique could improve diagnosis of vascular diseases, including arterial plaque characterization. Moreover, by summarizing all main information contained in the ultrafast Doppler acquisition, it permits a direct visualization of the data within the velocity profile. Here, we have compared our novel statistical technique to the standard pulse-wave Doppler approach during in vivo imaging of the human carotid artery. Notably, we achieved a greater than 4-fold reduction in intrinsic spectral broadening.