Cardiovascular flow velocity measurements by 2D Doppler imaging for assessment of vascular function

Clinical two-dimensional (2D) Doppler ultrasound flow velocity measurement is important for determination of arterial wall shear stress, blood-tissue exchange, myocardial and valvular function. Such 2D Doppler flow velocity images are usually displayed in color, superimposed on the gray-scale, cross-section structural images of the tissue. There are several limitations to this technique of flow measurement, some due to the instrumentation and some to the way the measurement is made. In this report we concentrate on the latter, identifying the main causes of errors and distortion, and outlining the methodology for minimizing them. The suggested method takes into account the spatial location and orientation of both the ultrasound transducer and the blood vessel. It allows quantification of vascular flow patterns, thus enhancing the usefulness of this important non-invasive diagnostic tool.