Angiography using ultrasound

In an ultrasonic imaging apparatus comprising an ultrasonic emitter, a receiver, a processor, and a display, a method for performing angiography of a subject under examination comprising the following steps:

• a. using said ultrasonic emitter, emitting a set of ultrasonic reference pulses along each of a series of parallel vectors in said subject under examination;
• b. using said receiver, receiving each of a plurality of echo signals generated by a reflection of said ultrasonic reference pulses in said subject under examination;
• c. for each of said plurality of received echo signals, obtaining a plurality of data samples from said plurality of received echo signals, each of said data samples representing points along each of said series of parallel vectors in said subject, said plurality of data samples each including a frequency shift from each of said set of ultrasonic reference pulses;
• d. successively removing from each of said plurality of data samples a plurality of basis functions to remove clutter from said plurality of data samples and generate a plurality of averaged processed signals;
• e. temporally filtering each of said plurality of averaged processed signals with each of a plurality of signals which have been displayed in a previous time period to generate a plurality of second signals, said temporal filtering using a filter which is approximates a full cardiac cycle of said subject under examination;
• f. converting each of said second plurality of signals to a color value to generate a first plurality of color values, each said color value of said first plurality of color values within a range of color values from said first color value to a second color value, wherein said first color value represents a minimum amplitude of said second plurality of signals to be displayed and said second color value represents a maximum amplitude of said second plurality of signals to be displayed;
• and
• g. displaying said first plurality of color values on said display at positions on said display corresponding with said points along each of said series of parallel vectors in said subject.