In recent years, it is possible to perform an ultrasound scan (called “an all-raster parallel simultaneous reception”) where either a plane wave or a diffuse wave is transmitted, and reflected-wave signals are received in a real-time manner by all the reception raster elements within an ultrasound frame with respect to the transmission at a time. Further, a blood flow display system (called “an ultrahigh-speed framerate method”) is known in which the all-raster parallel simultaneous reception is applied to a blood flow imaging method (called “a high framerate method”) utilizing an ultrasound scan (called “a high framerate ultrasound scan”) in which data sequences between frames are used as Doppler data sequences.
According to the ultrahigh-speed framerate method, for example, when the transmission interval of the ultrasound waves at a time is 200 μs, the framerate can be calculated as 5,000 frames per second (fps). Further, Moving Target Indicator (MTI) filters are capable of processing frame data corresponding to any number of frames. In other words, because the ultrahigh-speed framerate method is capable of arranging the transmission interval of the ultrasound waves to match the framerate, it is possible to obtain an infinite time period for observation while ensuring display at a high framerate and a high folding velocity. In other words, by implementing the ultrahigh-speed framerate method, it is possible to structure a steep MTI filter having a low cut-off frequency. With these arrangements, according to the ultrahigh-speed framerate method, by eliminating as many clutters as possible, it is possible to detect blood flows in a wide range from blood flows having lower flow rates to blood flows having higher flow rates.
Further, as an adaptive example of the ultrahigh-speed framerate method, observing moving images at 5,000 fps in a slow playback mode makes it possible to visually recognize complex flows of blood flowing through the heart, the carotid artery, or the like. Furthermore, tracking a speckle in a blood flow makes it possible to display a flow of blood with a two-dimensional vector.