Ultrasonic synthetic aperture imaging used to measure 2D velocity fields in real time

Synthetic aperture techniques have been adopted to improve spatial resolution and provide an extremely fast 3D data acquisition modality for measuring the velocity of relatively fast moving structures such as the heart muscle or blood in arterial stenoses. Synthetic aperture techniques require the use of a 2D transducer array as well as very fast signal acquisition and processing capabilities. A laboratory C-mode Doppler device has been built for the evaluation of the new procedure. Experiments were carried out with a laboratory flow model which was filled with a blood-mimicking fluid. The spatial resolution as well as the accuracy of the measured velocity field have not been achieved simultaneously by color Doppler techniques. As a consequence of the parallel interrogation of the sample volumes, spatial resolution is not dependent on time or velocity resolution. It can be refined by using an array with a larger overall area and an increased number of elements as well as a corresponding extension of the electronic circuitry