Diagnostic ultrasound system

A diagnostic ultrasound system for displaying a color image of a motion of a tissue contained on a subject's tomographic plane, said color image being superposed on a B-mode tomographic image of the subject's tomographic plane, said system comprising:

• means for scanning an ultrasonic pulse signal along the tomographic plane to acquire an electrical echo signal corresponding to a reflected ultrasonic signal from the tomographic plane;
• means for extracting a Doppler signal from the echo signal, said Doppler signal being Doppler-shifted by the motion of the tissue;
• means for calculating velocity data concerning the motion of the tissue for respective sample points on the tomographic plane on the basis of the Doppler signal;
• means for forming data of the B-mode tomographic image on the basis of the echo signal;
• means for blanking the velocity data at every sample point when each of the velocity data exceeds a specified threshold;
• and
• means for displaying the color image by coloring the velocity data and by superimposing the velocity data subjected to blanking by the blanking means on the data of the B-mode tomographic image.

A diagnostic ultrasound system for displaying a color image of a motion of a tissue contained on a subject's tomographic plane, said color image being superposed on a B-mode tomographic image of the subject's tomographic plane, said system comprising:

• means for scanning an ultrasonic pulse signal along the tomographic plane to acquire an electrical echo signal corresponding to a reflected ultrasonic signal from the tomographic plane;
• means for extracting a Doppler signal from the echo signal, said Doppler signal being Doppler-shifted by the motion of the tissue;
• means for calculating velocity data concerning the motion of the tissue for respective sample points on the tomographic plane on the basis of the Doppler signal;
• means for forming data of the B-mode tomographic image on the basis of the echo signal;
• means for setting a scale along which each of the velocity data over a measurable band of frequencies of the Doppler signal is assigned to each gradation data for color display, said measurable band of frequencies being limited by a pulse repetition frequency of the ultrasonic pulse signal and a given low-velocity band of the measurable frequency band being enhanced in the gradation data than a remaining velocity band of the measurable band;
• means for converting the velocity data into the gradation data according to the scale;
• means for blanking either one of the converted gradation data and the calculated velocity data at every sample point when each of said either one exceeds a specified threshold;
• and
• means for displaying the color image by coloring the velocity data and by superimposing the velocity data subjected to blanking by the blanking means on the data of the B-mode tomographic image.