A large aperture row column addressed probe for <i>in vivo</i> 4D ultrafast doppler ultrasound imaging.

4D Ultrafast ultrasound imaging was recently proposed to image and quantify blood flow with high sensitivity in 3D (Provost et al., 2014) as well as anatomical, mechanical or functional information. In 4D Ultrafast imaging, coherent compounding of tilted planes waves emitted by a 2-D matrix array are used to image the medium at high volume rate. 4D ultrafast imaging, however, requires high count electronics (&gt;1000) to drive those probes. Alternatives approaches have been proposed and investigated to efficiently reduce the density of elements such as sparse or under-sampled arrays while maintaining a decent image quality and high volume rate. The row-columns configuration presents the advantage of keeping a large active surface with a low amount of elements (Morton and Lockwood, 2003) (Rasmussen et al., 2015) and a simple geometry. In this study, we designed and built a new Row and Column Adressed (RCA) probe dedicated to vascular imaging and investigated it with a specific Orthogonal Plane Wave (OPW) compounding strategy (Flesch et al., 2017). Using this prototype, 4D ultrafast Power Doppler imaging of a large volume of 25.6×25.6 mm² up to 40 mm depth is demonstrated in vitro on flow phantoms and vivo on the carotid artery of a healthy volunteer at a volume rate of 834 Hz.