Color Doppler imaging on a smartphone-based portable US system: Preliminary study

There is increasing interest in the point-of-care US system using smart devices, such as a tablet PC and a smartphone, due to their high accessibility and portability. To meet this growing interest, our group recently has developed a smartphone-based portable US system but it only provided B-mode imaging. In this paper, we present the realization of the Color Doppler (C-mode) imaging on the aforementioned system to provide the functional information such as velocity of blood flow. The smartphone-based portable US system consists of a smart probe and a smartphone. To implement the C-mode processing, we redesign the sequence of the data acquisition on a FPGA (Spartan 6 LX150, Xilinx Inc., USA) of the smart US probe. On the other hand, in the smartphone (Galaxy S5 LTE-A SM-G906, Samsung Electronics Inc., Korea), a real-time C-mode back-end processing is implemented. The performance of the proposed C-mode imaging is evaluated by the phantom study and in vivo study. As a result, the developed system can provide the quantitative information of the velocity and the distribution of the blood flow by B&C-mode images. Also, as the view depth is 4 cm, the proposed C-mode image processing satisfies the requirement of the real-time operation by providing processing time of 22 msec shorter than the data acquisition time (i.e., 34 msec).