Abstract: An ultrasonic diagnostic imaging system and method are described by which a fundamental frequency signal is transmitted into the body and harmonic (nonlinear) echo returns are received from the transmission. The harmonic echo signals are Doppler processed and displayed. The harmonic Doppler signals may be displayed alone, or in combination with a fundamental frequency or harmonic grayscale image. In a preferred embodiment harmonic signals returned from moving tissue are segmented on an intensity or frequency basis and displayed. The inventive apparatus and method provide highly resolved ultrasonic images of moving tissue which are substantially unobscured by image clutter from structures or tissue in the near field.

Abstract: The Doppler imaging of blood flow or slowly moving tissue at high frame rates of display is performed by oversampled acquisition of a Doppler ensemble from the body and display of Doppler information within a display range of Doppler values which is less than the range defined by said rate of oversampling. Preferably, Doppler information is acquired at the highest PRF for the depth of Doppler imaging. In one embodiment Doppler data is scaled in proportion to the ratio of the acquisition PRF to the display PRF. Alternatively, an embodiment of the present invention performs Doppler estimation by autocorrelation or spectral analysis which operates upon nonadjacent samples in the Doppler ensemble.

Abstract: A method and apparatus are presented for tracing the border of tissue through temporally acquired scanlines comprising the steps of reducing noise in the scanlines, producing a map of tissue edges from the scanlines, denoting a tissue border to be traced, and using velocity information corresponding to tissue edges to trace the denoted border.

Abstract: A velocity estimation technique is provided for a pulse-echo ultrasonic diagnostic system in which a two dimensional array of samples is acquired from a sample volume. The two dimensions of the array are depth, in which echo signal samples are acquired in response to transmission of a pulse to the sample volume, and pulse time, in which samples are acquired in response to transmission of the pulses in the pulse ensemble to the sample volume. Two autocorrelation calculations are performed on the array, one in the depth dimension and another in the pulse time dimension to yield two correlation functions, the first related to echo frequency and the second related to the Doppler frequency. The two correlation functions are then employed in a Doppler velocity estimation to determine the velocity of motion at the sample volume.