| 摘要 |
A method and apparatus for recursive ultrasound imaging using a Synthetic Transmit Aperture and by which a new frame is created at every pulse emission. In receive, parallel beam forming is implemented. The beam formed RF data is added to the previously created RF lines. To keep the level of the signal, the RF data obtained previously, when emitting with the same element, is subtracted from the RF lines. Up to 5000 frames/sec can be achieved for a tissue depth of 15 cm with a speed of sound of c=1540 m/s. The high frame rate makes continuous imaging data possible, which can significantly enhance flow imaging. A point spread function 2° wide at -6 dB and grating lobes of <=-50 dB is obtained with a 64 elements phased array with a central frequency f0=3 MHz using a sparse transmit aperture using only 10 elements (Nxmt=10) during pulse emission. The corresponding images have the quality of a dynamically focused image in transmit and receive. The dynamic focusing gives a small sampling volume and the capability to view small blood vessels and obtain the velocity profiles within the vessels with lower variance than with normal imaging. |
