Abstract: By scanning a cross-section of an inside of a subject through an organ of interest with an ultrasonic wave it is possible to generate tissue cross-sectional data relating to the cross-section and motion velocity data relating to the region of interest. The motion velocity data is comprised of transmit/receive direction components of the ultrasonic wave. In order to obtain a motion velocity, or its near-motion velocity, of a direction of interest, it is necessary to angle-compensate the motion velocity data in accordance with a given direction of interest. According to the present invention, the direction-of-interest necessary to effect the angle compensation is assumed based on the contour of the organ of interest which can be extracted from the tissue cross-sectional data.

Abstract: A method and system for acquiring data in an ultrasound system are provided. A transducer is operatively connected to a transmit beamformer and a receive beamformer. The receive beamformer is configured to obtain a first value associated with a fundamental frequency interleaved with a second value associated with a harmonic frequency. A first transmit signal is transmitted at a first frequency. A first echo signal is received in response to the first transmit signal. At least the first value associated with the first frequency is obtained from the first echo signal. An interleaved second transmit signal is transmitted at the first frequency or a second frequency. A second echo signal is received in response to the second transmit signal. At least the second value associated with a third frequency is obtained from the second echo signal. Images are generated and displayed based on the at least one first value and the at least one second value.

Abstract: An ultrasound color flow imaging system is programmed to operate in an adaptive manner. The operational adjustments are made based on the system gain setting or the transmit packet size or both. Based on these operator inputs, the transmit burst length is adjusted for optimum operation. In addition, the transmit peak amplitude and the bandwidth of the receive filter are adjusted as a function of the burst length adjustment.

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: A method and system for generating data for a spectral Doppler strip in an ultrasound system includes a beamformer that provides Doppler data to a signal processor. The signal processor applies an autoregressive model and determines autoregressive parameters responsive to the Doppler data. Information responsive to the autoregressive parameters is generated, and a window function is applied to the information. At least one spectrum responsive to the autoregressive parameter is estimated with a Fourier transform.

Abstract: An ultrasound color flow imaging system is programmed to optimize display images of power and velocity by automatically adjusting thresholds and a color map by using histograms of color flow data.

Abstract: A method of imaging to aid tissue viability determinations is provided. Tissue motion is detected for at least region of tissue. Perfusion is estimated as a function of intensity data and time for the region of tissue. An image responsive to the detected tissue motion and the estimated perfusion is displayed. A combination of tissue motion imaging and perfusion estimation provides an assessment of tissue viability. If tissue exhibits perfusion and motion, then the tissue is likely normal. Any other perfusion and motion characteristic combination indicates abnormal tissue viability.

Abstract: An interested region including an interested blood vessel of a subject is scanned by a plurality of ultrasonic waves so as to receive a plurality of echo signals. A plurality of Doppler signals is detected from the echo signals in connection with a plurality of sample points in the interested region. An average frequency of the blood current of the interested blood vessel, variance, and power are calculated based on the Doppler signals. A sample point positioned on the interested blood vessel is picked up from the plurality of samples every time phase based on the average frequency or power. A time curve is formed based on at least one of the average frequency of the picked up sample point, the variance, and power. Thereby, it is possible to compensate for the state that a sample volume is detached from the interested blood vessel as in the conventional case.

Abstract: A pulsed Doppler technique uses coded excitation on transmit and pulse compression on receive. Coded excitation allows a long transmit pulse to be compressed on receive such that most energy is concentrated in a short interval. In the case of a single coded transmit for each transmit focal position, the receive signals are compressed utilizing matched or mismatched filtering. In the case of a two or more coded transmits for each transmit focal position, the receive signals are compressed utilizing filtering coefficients which match the respective transmit codes during each firing. These techniques can be used to maximize Doppler sensitivity of a small but deep-lying sample volume. Alternatively, for a given transmit acoustic burst length and dosage, the sample volume can be reduced to achieve better spatial resolution without compromising sensitivity.

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: Continued bleeding into a pocket or hematoma in the cranium could exert pressure on the brain which would move it relative to the cranium to force the brain stem into the medulla oblongata to arrest breathing. Such brain micromovement is detected by projecting bursts of ultrasound into one or both of the temple areas of the cranium or into the medulla oblongata, and the readout of echoes received from different depths is displayed on a screen. The readout of the echoes indicates continued microshifts of the brain relative to the cranium. To differentiate microshifts of the brain relative to the cranium caused by continued intracranial bleeding as distinguished from pulsations of the brain relative to the cranium caused by supply of blood to the brain from the heart and return of blood from the brain to the heart, the timing of the bursts of ultrasound into the cranium is synchronized with the pulse indicated by a heart pulse monitor.

Abstract: A method for estimating a flow in an observation plane from the Doppler velocity distribution in the observation plane. A Doppler flow function is found from the Doppler velocity distribution by linear integration. A flow rate passing through a path perpendicular to a beam direction is found from the Doppler velocity distribution, and a Doppler flow range function representing a variation of this flow rate in the beam direction is calculated. The Doppler flow range function is separated into a linear boundary flow range function which is a two-dimensional component and a planar boundary flow range function which is a three-dimensional component. The planar boundary flow range function is approximated by a stepwise quantized planar boundary flow range function which varies in unit flow rate, and sink points and source points (simple sources) are determined based on a step position of this quantized planar boundary flow range function.

Abstract: A color flow imaging technique uses coded excitation on transmit and pulse compression on receive. Coded excitation allows a long transmit pulse to be compressed on receive such that most energy is concentrated in a short interval. Multiple transmit firings of the same coded pulse sequence are focused at the same transmit focal position with the same transmit characteristics. The receive signals are compressed utilizing matched or mismatched filtering. These techniques can be used to maximize color flow sensitivity in deep-lying regions. Alternatively, for a given transmit acoustic burst length and dosage, the spatial resolution can be improved without compromising sensitivity.

Abstract: An analytical method for automatic tracing of a Doppler time-velocity waveform envelope. At the core of this algorithm is a maximum frequency detection mechanism which is based on searching for the highest frequency bin whose spectral amplitude exceeds a certain noise threshold. The method is based on a theoretical noise amplitude distribution in the video spectral domain. In particular, the method uses a precise model of the statistical distribution of the video spectral power of white noise to establish a threshold for maximum frequency detection. Input to the noise model is the average white noise level in the video spectral display, which can be computed using either of two analytical methods.

Abstract: An ultrasound flow velocity and Doppler angle measurement method and system is provided for measuring the velocity and direction of a flow, such as the blood flow in a human body, in a non-contact manner through ultrasound means. In practical applications, this ultrasound flow velocity measurement method and system can be utilized, for example, in the field of physiological diagnosis for blood-flow velocity measurement to determine whether the patient suffers from blood vessel disorders, such as embolism and aneurysm. Precise measurement can be achieved through the use of just one set of ultrasound transducer in the system configuration; therefore, this ultrasound flow velocity measurement method and system is simpler in system configuration and more cost-effective to use than the prior art. Experimentation shows that the estimation has a standard deviation of less than 4.5.degree. for Doppler angle range from 45.degree. to 80.degree.. Therefore, the measurement results are trustworthy to use.

Abstract: A blood flow detection and imaging method and system is described for displaying images in accordance with signals transmitted from an intravascular ultrasound transducer probe. The image processor includes means for independently designating persistence factors for smoothing calculated speed and power of the dynamic portion of a field of view within a vasculature. Furthermore, the designation of a particular image point within a field of view as a dynamic image point (such as a blood flow region) as opposed to a static image point (such as a tissue region) is determined by averaging signal values for image points proximate to an image point of interest over both time and space.

Abstract: An ultrasound diagnostic apparatus including transmitting and receiving devices, and MTI filter units to eliminate clutter components from Doppler data sequences detected trough the transmitting and receiving devices. The diagnostic apparatus further includes A/D converters to convert the Doppler data sequences in analog to those in digital and transient response processing devices provided between the MTI filter units and the A/D converters to suppress influences of transient responses consisted in output signals of the MTI filter units due to at least either one of data discontinuity of the Doppler data sequences at the time starting point or abrupt changes thereof.

Abstract: A system is disclosed for performing ultrasonic color Doppler imaging to produce absolute velocity and flow direction information for complex media. Ultrasonic color Doppler beams are steered at two different angles and samples are taken at the points of intersection between the steered beams. The duplex color Doppler sample volumes are two overlapping sample volumes interrogated from different angles. Frequency-shift information provided by the color Doppler sample volumes are used to compute the absolute mean velocity and direction of motion of acoustic reflectors within the sample volumes. Velocity and direction data are computed for a two-dimensional array of duplex color Doppler sample volumes and mapped into a color scale to provide a spatial distribution of the velocity or direction of flow or motion of acoustic reflectors.

Abstract: An ultrasound imaging apparatus and method in which an ultrasound signal is transmitted a plurality of times in each scanning direction and its echo is received. A Doppler signal detected from a group of echo signals consisting of a train of sequential Doppler data for each spatial sample position in each scanning direction. The amount of instantaneous changes in a phase of a clutter component included in the Doppler signal is estimated, the clutter component occurring due to reflection of the ultrasound signal from an organ. A phase of the Doppler signal is corrected using the estimated amount of instantaneous changes in the phase. A constant value corresponding to the clutter component is subtracted from the Doppler signal of which phase is corrected, information representing a blood flow is extracted based on the Doppler signal of which clutter component is removed and the extracted information is displayed in color.

Abstract: A method for generating color Doppler images is implemented in real time using digital processing steps implemented on multi-purpose microprocessors. Processing is reduced by estimating velocity only when a tissue threshold decision for a given sample indicates that the sample is not tissue. Arc tangent calculations in the velocity estimation are performed using simplified look-up tables without sacrificing accuracy. One look-up table is lineraly quantized. A second is nonlinearly quantized.

Abstract: A method and an apparatus for increasing the spatial resolution and sensitivity of a color flow image while maintaining a desired acoustic frame rate. The ultrasound energy is concentrated at a more narrowly defined focal region, which allows for increased flow sensitivity and vessel filling. Better flow uniformity across the color region of interest is also achieved. The method uses multiple transmit focal zones, and transmit and receive apertures having low f-numbers. Using multiple focal zones with low f-numbers allows for tight focusing over a larger depth-of-field. Unique waveforms and unique gain curves are used for each focal zone. Each focal zone is fired on a separate acoustic frame. An adaptive frame averaging algorithm is used to blend together the in-focus data from each of these acoustic frames before the data is displayed.

Abstract: The energy, power or amplitude of Doppler or time shift information signals is compared to a threshold in order to select a large or small weighting factor for temporal persistence. In the event of a "flash" signal or strong arterial flow signal, a small weighting factor is chosen to reduce the extent of temporal persistence via feedback of the averaged value for the prior frames so that the effect of the "flash" or strong flow signal would quickly dissipate in the imaging of subsequent frames and good temporal resolution preserved for the current frames, while low energy flow signals would cause a large weighting factor to be selected to improve the signal-to-noise ratio of low energy signals. Similar effects can be achieved by clipping the signals to not exceed a certain threshold.

Abstract: An improved technique for providing persistence to velocity signals obtained by an ultrasound imaging system is disclosed. The velocity signals with appropriate persistence are then used to form an image on a display device so as to accurately depict fluid flow. The persistence technique intelligently decides whether or not to provide persistence to the velocity signals. In making these persistence determinations, the persistence technique not only avoids distorting the velocity values with corrupt signals, but also preserves directional flow information. The persistence technique can also make use of various thresholds to reduce errors (e.g., flash artifacts or random noise) as well as persistence of such errors.

Abstract: The method of the invention employs pulsed Doppler ultrasound signals to color image blood and tissue movement velocities in a body. The method initially images a movement with a transmitted ultrasound signal that manifests a current signal transmission frequency value and a current pulse repetition frequency (PRF) value. Those values exhibit a determined ratio R to each other. Thereafter, in response to an indication by the user that movement is to be imaged at a new depth, the method alters the current transmission frequency to a new frequency to provide improved signal back-scatter from movement at the new depth. Then, the current PRF is adjusted, automatically, to a new PRF value which, when compared to the new transmission frequency, manifests substantially the same determined ratio R that was present between the current transmission frequency and current PRF. The latter step assures that the mapping of movement velocity values to colors is maintained, notwithstanding use of a new transmission frequency.

Abstract: A Doppler ultrasound diagnostic apparatus equipped with Doppler detection units and a forward/reverse separating means in an audio signal output system, a complex Doppler signal control means which stores a complex Doppler signal received during the Doppler-mode period and reads out said complex Doppler signal during the B-mode period to use as a complex Doppler signal during the B-mode period, wherein said complex Doppler signal control means includes storage means for storing complex Doppler signals that are received during the Doppler-mode period; control means for reading out complex Doppler signals stored in said storage means in a reverse order during the B-mode period; complex frequency inversion means for inverting the frequency of the complex Doppler signals read by said control means in the reverse order from said storage means; and phase rotation correction means for correcting a difference in phase at a moment when the Doppler mode is connected to the B-mode for a complex Doppler signal from said

Abstract: A method for evaluating a varix, including the steps of: (a) placing a system for observing whether the varix is open or closed into a region adjacent to the varix; (b) placing a system for sensing pressure into a region adjacent to the varix; (c)temporarily increasing the pressure in the region adjacent to the varix so that the varix collapses; (d) simultaneously observing the varix with the observing system and monitoring the pressure in the region adjacent to the varix with the pressure sensing system when the varix closes or reopens. Also, a device for evaluating a varix, including: (a) a system for observing whether the varix is open and generating an observing system output; and (b) a system for sensing the pressure in the region adjacent to the varix and generating a pressure sensing output.

Abstract: A BcD mode ultrasound imaging system including a Doppler processor which is configured to receive a Doppler signal having components that are corrupted by residue from color mode interleaving. The Doppler processor is configured to analyze the residue effect and compensate for the residue by filtering the received Doppler signal.

Abstract: An ultrasound imaging system that utilizes a short sinusoidal pulse burst for excitation, and performs coherent detection of the reflected signal, resulting in improved signal-to-noise ratio. In addition, the polarity of the rate of change of parameters, principally density, is preserved by the coherent detection. This allows a density versus distance signal to be reconstructed by integrating the coherently detected signal. The system includes components to calculate and apply all necessary phase corrections.

Abstract: A method (280) and system (128) for selectively smoothing color flow images in a Doppler ultrasound system (100). A set of original digitized ultrasound signals is received for points (m, m-1, m-2) on a beamline (l-1), each point having associated with it a velocity signal (.phi..sub.j), a magnitude of autocorrelation signal (R.sub.i), and a power signal (P.sub.i). A point (X(1,1)) along a beamline is selected for processing. The set of digitized ultrasound signals is applied to a digital filter (152), and the digital filter computes a set of smoothed digitized ultrasound signals by computing an average velocity signal (.phi..sub.av), an average magnitude of autocorrelation signal (R.sub.av), and an average power signal (P.sub.av) of each point in the selected beamline and points in adjacent beamlines. For the selected point along the selected beamline, a selected velocity signal (.phi.(1,1)) is compared to a velocity threshold (V.sub.

Abstract: In an ultrasound imaging system, the mean velocity of a fluid flow, variance of velocity of the fluid flow and energy value of Doppler ultrasound signals from the flow in response to transmitted ultrasound are first estimated from autocorrelation values of the signals to form a set of parameters for a corresponding sampling time or a corresponding sampling location. An averaging process is then performed on two sets of the estimated parameters corresponding to a plurality of different sampling times in temporal filtering or on two sets of the estimated parameters corresponding to a plurality of different locations in spatial filtering. The filtered parameters are then compared to thresholds in a discrimination process to reject noise and clutter.

Abstract: In an ultrasonic diagnostic apparatus, ultrasonic pulse beams are transmitted into an organism, ultrasonic waves reflected within the organism are received to obtain received signals, and an image is displayed in accordance with the received signals thus obtained.

Abstract: A method and apparatus for ultrasonically producing 3-dimensional images in real time, wherein a device transmits an ultrasonic wave toward a solid bearing angle obtained by dividing into multiple portions a solid bearing angle subtended by a sonic field to be examined, and receives echoes therefrom, with the transmitted waves being sequential and the received echoes being concurrent multiple waves from each small solid angle, and a device for producing the 3-dimensional images by range gating the received echo signals in the depth direction of the sonic field being examined and then producing direct vision images in the direction of the transmitted ultrasonic waves based on the echo signals, wherein the range gated signals are quadrature detected in one embodiment and/or are subjected to 2-dimensional Fourier transformation in another embodiment.

Abstract: A probe in a hand held ultrasonic Doppler fetal heart beat detector and monitoring system comprising a crystal for transmitting ultrasonic energy, a variable power source connected to said crystal for driving the crystal at a selected power setting and a microprocessor for selecting a power setting for the variable power source.

Abstract: A phased array sector scanning ultrasonic system includes a separate receive channel for each respective element in an ultrasonic transducer array. Each receive channel imparts a delay to the echo signal produced by each respective element. The delayed echo signals are summed to form a steered, dynamically focused and dynamically windowed receive beam. A plurality of channels in the receiver are operated by respective receive channel control circuits to apodize the sampled echo signals produced by the transducer array elements with respective selected window function weighting factors as the echo signals are received. Each receive channel control circuit stores a set of window function weighting factors at successive address locations in a memory and includes an addressing circuit for producing an address useable by the memory to provide a desired window function weighting factor for each receive channel from the stored set.

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: An ultrasound imaging system enables discrimination between heart chamber blood flow and blood flow in a heart wall and includes a transducer for transmitting ultrasound pulses into a patient and for receiving ultrasound echoes from blood flow targets within the patient. A beam former/buffer converts the received ultrasound echoes into echo data patterns from which a relative velocity of a blood flow target within said patient is determinable. A strong filter preferentially enables passage of echo data pattern signals which represent a velocity that is higher than a velocity of echo pattern data signals from cardiac wall blood flow targets in the patient. A weak filter partially inhibiting echo signals from low velocity tissue targets.

Abstract: A user defines a line of study by two or more icons placed on a two-dimensional motion image. A velocity profile or the estimated spectra at each point along the line of study are displayed as a function of position along the line of study. The velocity and variance parameters displayed are computed in reference to velocity direction angles selected by the user. The information displayed is obtained from scan converted information to facilitate the process. One or more spectral strips may be displayed in addition at one or more range gate positions.

Abstract: Methods and systems for monitoring to assess the health of a fetus being carried within a mother. The methods include sensing fetal heart information using a fetal heart sensor; determining at least one fetal heart rate measure from the fetal heart rate information; detecting umbilical flow information relating to the flow of blood within the umbilical; deriving at least one umbilical flow indicator from at least the umbilical flow information; and analyzing the fetal heartbeat measure and umbilical flow measure to produce at least one fetal health parameter. The systems include the heartbeat sensor, umbilical flow detector, and a processor which allows analysis of the information obtained from the sensor and detector to provide an indication of fetal health.

Abstract: An ultrasound imaging system for displaying edge-enhanced topographic flow power data surrounded by B-mode anatomical data without masking out any significant edge-enhanced topographic flow power data and without displaying any significant flow power background noise. An improved high-pass topographic filter is used to enhance the edges of the flow in the displayed image in both the horizontal (lateral) and vertical (range) directions. The two-dimensional topographic filter is a digital filter with three taps in each dimension and is incorporated in the acoustic line memory. Also, the raw flow power data is compressed down to 7 bits in such a way that the transfer function is shifted away from zero input power. In this way, the system gain can be set to effectively zero out most of the background noise. After the flow power data passes through the high-pass topographic filter, it is mapped to values between -128 and +127 (8 bits) with zero in the middle.