SYSTEM FOR RAPIDLY CALCULATING EXPANSION IMAGES FROM HIGH-FREQUENCY ULTRASONIC ECHO SIGNALS

摘要

Elastography is an ultrasound imaging method which renders visible the elastic properties of biological tissue, which is frequently not possible with conventional ultrasound images. According to said method the tissue is compressed and the ultrasound images taken before and after compression are compared so that an image can be obtained of local tissue expansion and hard and soft tissue types can be distinguished. With this method time shifts of corresponding ultrasound echo signals are calculated locally in one or more points, a process which was very time-consuming using known methods. The invention provides for a system for rapidly calculating expansion images from ultrasound echo signals, which iteratively determines the zero point of the phase of the correlation function of the echo signals downward-mixed in the base-band. This makes it possible to calculate the time shifts of corresponding echo signals rapidly and accurately and thus to determine tissue expansion values which can, for example, be calculated in real time and represented parallel to the conventional ultrasound B-mode image.