Some perturbations on the ultrasonic measurements in phantoms using transit-time flow-metering systems

The use of test and calibration systems has great importance during the design & development of medical ultrasonic devices. In the particular case of analyzing in a laboratory new transit-time designs (for flow estimation in cardiac vessels) using phantoms (artificial tissues), it is necessary to confirm the existence of a certain linearity in the measurements, and also to achieve accurate calibrations of those in absolute value. However, the distinct acoustic and elastic properties encountered in the walls of the artificial blood vessels, commonly used in laboratory (based on plastic o silicone materials), during the design and development phases, can significantly alter these results, leading en many cases to wrong conclusions in laboratory evaluations. This work is devoted to study the influence that the characteristics of artificial vessels, respect to the real blood vessels, can exert in the measures acquired by an electronic broadband Transit-Time system, which is due to the distinct propagation times through the walls of the phantom devices.