Ultrasonic Perfusion Estimation in Calf Muscle

In this project, The investigators will use Alpinion ECUBE-12R (Alpinion, Bothell, WA) US platform. This state-of-the-art research US machine provides beam formed as well as Plane-Wave imaging options that allow high frame rate imaging. The investigators have characterized the acoustic output of this system for safe human studies and obtained the IRB approval for human studies. It should be noted that our technique is not limited to the Alpinion system; the investigators can also use other US systems, such as Verasonics, Vantage, (Redmond, WA). This technique can be adapted to other modern US machines in the future.