Ultrafast plane wave imaging: Doppler frequency distribution

Ultrafast plane wave imaging enables the acquisition of thousands of temporal samples per second over a large field of view compared to the scarce 100 frames per second of a conventional focused mode. However, a main problem remains: How to compute with this huge amount of data relevant information for diagnosis? In this article, we present a statistical technique that analyses the spatio-temporal distribution of the Doppler frequency. This statistical technique gives a two dimensional output frequency versus time as the standard pulse wave Doppler commonly used by sonographers but reduces dramatically the presence of geometric broadening on Doppler spectrums. Thereby, this technique becomes highly sensitive to the type of the flow profile and turbulences which could help to diagnosis vascular diseases as plaques in the carotid artery. By summarizing all the main information contained in the ultrafast acquisition it permits a direct visualization of the flow speed and its gradient. We compare this statistical technique and a standard pulse wave Doppler in vivo on the carotid artery.