Diasonics Ultrasound, Inc.

Diasonics, Inc.

University of Michigan

Ray S Spratt

Steven F Forestieri

Gregory Sharat Lin

Jonathan M Rubin

J Brian Fowlkes

Kenneth R Erikson

Wilbur A Reckwerdt

Sandra A Briggs

Dennis Paul

Ronald S Adler

Syed O Ishrak

A method and apparatus for determining resistance and pulsatility indices of a flow of material, such as the flow of blood in the human body. This may be implemented, for example, in a color flow module in an ultrasonic imaging system for display of the pulsatility or resistance index in two dimensions and in different colors to allow discrimination between veins and arteries and detection of pathologic elevation of vascular resistance in a clinical survey mode of the system. The resistance index is determined from the ratio of a unipolar variation estimate of a velocity of the flow material divided by a peak velocity. The variation estimate may be one of the following: a difference between a peak velocity of the flow of material and a second minimum (if unipolar) or negative (if bipolar) velocity of the flow of material, a standard deviation .rho. of the velocity of the flow of material, a square root of a value at a first peak of an autocorrelator of the velocity of the flow of material, and a square root of a value at a second peak of the autocorrelator of the velocity of the flow of material.

Real-time two-dimensional resistance and pulsatility mapping

A method and apparatus for generating three-dimensional (3D) images of flow structures and their flow lumen using ultrasound techniques. According to one aspect of the invention, a border between a flow region and a non-flow region is used to render a three-dimensional image of the flow lumen of the flow structure. The images may be viewed in real-time and/or stored on a machine-readable medium. In one embodiment, the three-dimensional images may be manipulated in a number of viewing directions/angles/distances/positions/styles. In one embodiment, a flow lumen may be displayed using a virtual angioscopic view.

Method and apparatus for three-dimensional flow lumen imaging

A method for quantitatively estimating the amount of tissue that contains moving blood using power Doppler ultrasound. A region of interest is identified from a frozen image (i.e., a snapshot screen display created by displaying the last real-time image for a given scan). The region of interest is specified by using a pointing device (e.g., a mouse). An object that contains one hundred percent blood flow and is located at the same depth as the region of interest, but not necessarily inside the region of interest, is identified and the corresponding power noted and designated as the reference power level. The display is adjusted to show the one hundred percent blood flow vessel in a designated color (such as, for example, green) and all other power levels are normalized to the reference power level. The fractional blood volume is quantitatively estimated by summing the normalized Doppler power levels in a region of interest and dividing the sum by the number of pixels in region of interest. The numerical result for the specified region of interest may be shown on the display of the ultrasound scanner.

Fractional moving blood volume estimation with power doppler ultrasound

A method and apparatus for automatically measuring the circumference of a first region enclosed in a second region internal to a living organism, wherein the first and second regions consist of different cellular matter. One embodiment of the present invention includes generating a point inside an interior of the first region. A set of radial vectors are then generated, which emanate from the point in the interior of the first region. A path is then selected which intersects the set of radial vectors. The path is selected by identifying a distinguishable ultrasonic measurement along the respective radial vectors. A length of the selected path is then measured to generate the circumference of the first region.

Method and apparatus for measuring fetus head and abdominal circumference

A method and apparatus for automated measuring of a diameter of a first region enclosed in a second region internal to a living organism, wherein the first and second regions consist of different cellular matter. One embodiment of the invention includes generating a plurality of trial diameters, wherein each trial diameter includes an inner and outer region and has a different length. An ultrasonic measurement is taken of the inner region and the outer region for each trial diameter. The difference is determined for the ultrasonic measurements corresponding to the inner and outer regions of each trial diameter. The trial diameter which most closely corresponds to the diameter of the first region is then selected, wherein the difference of the ultrasonic measurements corresponding to the inner and outer regions is greatest for the trial diameter which most closely corresponds to the diameter of the first region.

Method and apparatus for automated vascular diameter determination

A method and apparatus for displaying an image representing the flow of a substance in a scanned area. An Angio scanner scans a region of tissue and generates Ultrasound Angio data representing the flow of blood in the region of tissue. Relatively small blood flows are difficult to detect in images based solely on Angio data. To enhance the visibility of small blood flows, spatial derivative values are calculated from the Angio data. A fraction of the original Angio data plus a bias is summed with the spatial derivative values to generate composite values. An image of the scanned region is displayed with colors or grayscale shades based on the composite values. The resulting image depicts blood vessels in an edge-enhanced format, giving a three-dimensional appearance.

Method and apparatus for displaying angiographic data in a topographic

Method and apparatus for performing angiography of a subject under examination in an ultrasonic imaging apparatus. A set of ultrasonic reference pulses along each of a series of parallel vectors is emitted into the subject under examination, echoes are received, and a plurality of data samples are obtained. From each of the plurality of data samples a plurality of basis functions are removed to remove clutter and generate a plurality of processed samples. The processed samples are averaged and temporally filtered with signals displayed in a previous time period to generate a second averaged signals. The temporal filtering is performed using a filter coefficient which approximates a full cardiac cycle of the subject under examination. Each of the second plurality of signals is converted to a color value to generate a first plurality of color values within a range of color values from the first color value to a second color value, wherein the first color value represents a minimum amplitude of the third plurality of signals to be displayed and the second color value represents a maximum amplitude of the second plurality of signals to be displayed. The first plurality of color values is displayed on the display at positions on the display corresponding with the points (color sample volumes) along each of the series of parallel vectors in the subject.

Angiography using ultrasound

An apparatus for temporal filtering in an ultrasonic imaging system. The apparatus has a means for storing previous imaging information from a previous time period and a means for storing current imaging information from a current time period. Means for determining the larger of the current and previous imaging information is provided and a means is provided for generating an alpha value responsive to the larger information. The alpha value ranges between a minimum and maximum values and has the maximum value when the larger information has a large frequency and has the minimum value when the larger information has a small frequency. Means for generating output imaging information is provided, the output imaging information generated by multiplying the current imaging information by alpha and summing it with the product of the maximum value minus alpha and the previous imaging information. The apparatus provides a means for heavily averaging the imaging information for small frequencies of the larger information and maintaining the pulsatility of large frequencies for fast moving blood velocities. In the preferred embodiment, errors and noise are minimized at frequencies near the baseline, and frequencies near Nyquist are not averaged at all. In one embodiment the apparatus comprises a lookup table.

Temporal filtering of color doppler signal data

An ultrasound imaging system for performing dynamic focusing of ultrasonic waves during transmit and receive. The present invention includes a method and a means for transmitting ultrasonic waves to a multiple depths within a body. The present invention optimizes the transmit frequency for each of the multiple depths to localize the energy of the ultrasonic waves. The present invention also includes a method and means for performing dynamic receive focusing of the reflected ultrasonic waves produced by discontinuities in the body, such that it is focused to receive ultrasonic waves from the depth at which the transmitted ultrasonic waves are focused.

Method and apparatus for focusing transmission and reception of

An apparatus and method for clutter elimination from signals which digitizes a signal to generate n samples of the signals. M basis functions (such as various levels of filters) are fit to the n samples. An i+1 basis function of the m basis functions is iteratively subtracted from each of the n samples, and the difference is stored in an i difference signal until the i+1 difference signal is less than a threshold. In various embodiments, the threshold may be an absolute noise floor (R.sub.O.sup.min) preset by a manufacturer or a user. In other embodiments, the threshold may be based upon an absolute or relative predictor error of the signal once the basis function (filter) has been removed. The i difference signal may be used for performing a frequency estimate of the signal.

Automatic clutter elimination

Signal processing apparatus and methods for elimination of undesirable clutter signals from desirable signals. This is performed without the use of filters by subtracting orthonormal basis functions from signal samples until the appropriate degree of clutter removal is achieved. Estimates of frequency information such as Doppler shifts due to fluid flow may thus be achieved with superior discrimination of true flow signals from sources of clutter or artifact, greater sensitivity to low flow rates, minimal computational effort and with fewer samples than the prior art.

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San Jose, CA, United States of America

Ray S Spratt