CONTRAST-MEDIUM ASSISTED FLUID-FLOW MEASUREMENTS

In this paper the development and evaluation of two new approaches for ultrasound time-domain fluid flow measurements by tracking echoes sca ttered by a contrast agent following injection of a bolus of the contr ast agent are described. Their feasibility was investigated by measuri ng velocity or velocity profile of blood flowing in a mock circulatory loop in vitro. Measurements were made with a one transducer intravess el approach and a two transducer extravessel approach. A hybrid cluste r or vector cross-correlation method was used to track the motion of t he scatterers in the two transducer time-domain method. This cluster o r vector cross correlation method was developed to reduce the ambiguit y resulted from misregistration which is a common problem in target tr acking by correlating signal patterns. The experimental results show a good agreement between the measured data and those estimated from tim ing the volume. Although the discussions given in this paper pertain o nly to blood flow measurements, there is no reason to indicate that th ese approaches can not be used for fluid flow measurements in an indus trial environment if suitable contrast agents can be developed.