Experimental investigation and finite element simulation of streaming in blood in cylindrical models

Conventional ultrasound imaging sometimes experiences difficulties of distinguishing between stagnant blood from tissue, and clotted from unclotted blood. This distinction may have high value in managing trauma patients with internal hemorrhage. Acoustic streaming is a physical phenomenon resulting from the momentum transfer from an ultrasound beam to the fluid medium due to attenuation. The presence of streaming in a sonographically indeterminate region can help detect a pool of unclotted blood from clots or other soft tissue. We report here a quantitative study of streaming in blood in a tubular model and a large open space. The streaming was detected with real-time color Doppler imaging. The experimental results were compared with the analytical solution and finite element simulation. This study suggests that streaming velocity will approach an asymptotic value in large hematomas.