Ultrasound Particle Image Velocimetry: measuring blood flow in an nonintrusive way

Recently, a new technique has been developed that can give insight in local hemodynamic conditions (e.g. blood flow patterns, forces on the blood vessel walls). This information is vital for understanding and monitoring the development of cardiovascular diseases (such as atherosclerosis). Ultrasound Particle Image Velocimetry is an adaptation of the conventional ultrasound ("echo") imaging. Rather than taking single images of a flow, we record a rapid sequence of images. We then find the displacement of so-called "tracers" in these images, so that we can obtain a snapshot of the blood flow velocity. These tracers can be red blood cells or artificially introduced bubbles ("contrast agent"). While "proof-of-principles" have been demonstrated, see e.g. Poelma et al. (2009), we want to see if we can improve the accuracy of this technique. To do this, as systematic study will be performed on a benchmark flow (e.g. Poiseuille flow). By varying both the imaging acquisition and post-processing parameters, we hope to find the optimal conditions for flow measurement. The experimental work will be done in collaboration with Imperial College London (Bioengineering department).

 References

C. Poelma, J. M. Mari, N. Foin, M.X. Tang, R. Krams, C.G. Caro, P.D. Weinberg and J. Westerweel (2009) "3D Flow
reconstruction using ultrasound PIV" Experiments in Fluids (in print, available at http://www.springerlink.com/content/y47223u46x825848/)