Application of Digital Particle Image Velocimetry to the Study of Pathological Flow Fields

Flow visualization using dye or imbedded markers has long been a valuable tool for the qualitative assessment of flow fields in models of cardiovascular architecture, including curved tubes, branches, stenoses, and the left ventricle. With the advent of Laser Doppler Anemometry (LDA), quantitative measurements of velocity, including turbulent fluctuations, became possible. However, full flow field visualization is a time-consuming task using LDA single point velocity measurements, and is quite cumbersome for complex cardiovascular geometries and time varying flow. Recent advances in video and computer technology have spurred the development of Digital Particle Image Velocimetry (DPIV) techniques, whereby entire two dimensional vector fields may be measured instantaneously. In our laboratory, we are utilizing DPIV measurements to validate numerical simulations of flow fields created by various pathologies, including a stenosis, an aneurysm, and abnormal left ventricular wall motion created by local ischemia.