Abstract: Systems and methods are described for tracking motion in a medical imaging system. The methods use landmark sets including hard landmarks and soft landmarks. The systems can include means for generating a landmark set, means for constructing a landmark set spatial relationship, means for computing a context similarity measurement, means for cost function construction, and means for cost function minimization and motion estimation. The invention provides advantages because, among other reasons, the use of a cost function of two or more variables, where the cost function is defined over members of the landmark set collection, and the cost function subject to at least two constraints and the landmark set stability in terms of context similarity measurements and spatial relationship provide effective and robust motion tracking.

Abstract: Methods and systems vary the elevation beam pattern during an imaging session. A user based or automatic search mode is provided where one or more elevation beam thicknesses are used, and then a diagnosis mode is provided where an optimal or narrow elevation beam thickness is used for continued imaging. 1.25, 1.5, 1.75 and 2D arrays are used to obtain frames of data responsive to the varied elevation beam pattern.

Abstract: Sidelobe levels of bipolar and unipolar waveforms are suppressed. Bipolar and unipolar transmit waveforms are generated with a coded excitation, such as a chirp coding, and pulse width modulation. For harmonic, such as second harmonic, imaging, the fundamental transmit frequency of the transmit waveform is centered at a lower end of the bandwidth of the transducer. The transducer filters higher frequency components of the transmit waveform differently than lower frequency components. To generate the desired acoustic waveform, the transmit waveform generated for application to the transducer is adjusted to account for the frequency response of the transducer. For example, higher frequency parts of a chirp waveform has more pulse width modulation or narrower pulse widths to account for lesser magnitude reductions. Multiple transmit waveforms may be combined to reduce sidelobes for fundamental or second harmonic imaging. Two coded excitation waveforms are generated.

Abstract: A method and system for quantification of strain imaging is disclosed. The method and system comprises performing a motion analysis on the at least two regions of interest. The method and system further includes providing a strain estimate for each of the at least two regions of interest and comparing the strain estimates of each of the at least two regions to quantify the strain for the at least two regions of interest. A system and method in accordance with the present invention provides for strain quantification based on conventional B-mode images. Using this technique, the strain of regions of interest (ROI) defined by users can be determined and quantitative comparisons can be effectively made in real time. The strain quantification can be used to determine tissue's properties and can potentially be applied in breast imaging as well as cardiac imaging.

Abstract: Three or four-dimensional ultrasound data acquisition for extended field of view imaging is provided. Multiple volumes are registered with respect to each other and spliced together to form an extended volume. The extended volume is a contiguous volume larger than a volumetric region that a multi-dimensional or wobbler transducer array is capable of imaging without movement. Information representing different volumes is registered with respect to each other by sensing the transducer position associated with each of the different volumes. The position is sensed using a position sensing mechanism, such as magnetic optical or gyroscope measurements. Acoustic data may be used to determine decorrelation of speckle or correlation of features to sense position. After the volumes are registered, any overlapping regions are compounded. The resulting extended field of view volume is displayed and manipulated for viewing by the user.

Abstract: Methods and systems for detecting a border in a medical image are provided. A boundary is chosen as a connected curve whose tangent is substantially perpendicular to the gradient of the image everywhere along the curve. As an alternative to a tangent, a normal or other border direction may be used. At a given point within the image, the tangent to the boundary and the image gradient direction are orthogonal. Using an initial boundary detection, the boundary associated with the minimum cost or associated with the closest boundary where the boundary tangent and the image gradient directional are orthogonal for locations along the boundary is identified. By refining an initial border location to minimize divergence from the boundary tangent being orthogonal to the image gradient direction or by identifying a border based on the orthogonal relationship, accurate border detection may be provided in ultrasound images as well as other medical images.

Abstract: Methods and systems for improving an ultrasound image quality are provided. On demand transmission of unsustainably high power ultrasonic pulses are temporary or spatially interleaved with low power, zero power, or standard ultrasonic pulses. In response to a user initiated trigger, a physiological trigger, a system trigger, or external equipment trigger, the unsustainably high power pulses provide better signal-to-noise ratio and/or allow increased imaging frequencies for difficult to image patients in any of various modes, such as B-modes, harmonic B-mode responsive to tissue or contrast agent, or color flow modes. Unsustainably high power ultrasonic pulses cause an increase in the tissue temperature within the body and at the interface between the transducer and the skin. Standard imagining or standard high power pulses may increase either temperature by around 6° C., such as from a body normal 37° C. to an average of 43° C. over time.

Abstract: Methods and systems for detecting a border in a medical image are provided. A boundary is chosen as a connected curve whose tangent is substantially perpendicular to the gradient of the image everywhere along the curve. As an alternative to a tangent, a normal or other border direction may be used. At a given point within the image, the tangent to the boundary and the image gradient direction are orthogonal. Using an initial boundary detection, the boundary associated with the minimum cost or associated with the closest boundary where the boundary tangent and the image gradient directional are orthogonal for locations along the boundary is identified. By refining an initial border location to minimize divergence from the boundary tangent being orthogonal to the image gradient direction or by identifying a border based on the orthogonal relationship, accurate border detection may be provided in ultrasound images as well as other medical images.

Abstract: Methods and systems for improving an ultrasound image quality are provided. On demand transmission of unsustainably high power ultrasonic pulses are temporary or spatially interleaved with low power, zero power, or standard ultrasonic pulses. In response to a user initiated trigger, a physiological trigger, a system trigger, or external equipment trigger, the unsustainably high power pulses provide better signal-to-noise ratio and/or allow increased imaging frequencies for difficult to image patients in any of various modes, such as B-modes, harmonic B-mode responsive to tissue or contrast agent, or color flow modes. Unsustainably high power ultrasonic pulses cause an increase in the tissue temperature within the body and at the interface between the transducer and the skin. Standard imagining or standard high power pulses may increase either temperature by around 6° C., such as from a body normal 37° C. to an average of 43° C. over time.

Abstract: Systems and methods are described for tracking motion in a medical imaging system. The methods use landmark sets including hard landmarks and soft landmarks. The systems can include means for generating a landmark set, means for constructing a landmark set spatial relationship, means for computing a context similarity measurement, means for cost function construction, and means for cost function minimization and motion estimation. The invention provides advantages because, among other reasons, the use of a cost function of two or more variables, where the cost function is defined over members of the landmark set collection, and the cost function subject to at least two constraints and the landmark set stability in terms of context similarity measurements and spatial relationship provide effective and robust motion tracking.

Abstract: Methods and systems vary the elevation beam pattern during an imaging session. A user based or automatic search mode is provided where one or more elevation beam thicknesses are used, and then a diagnosis mode is provided where an optimal or narrow elevation beam thickness is used for continued imaging. 1.25, 1.5, 1.75 and 2D arrays are used to obtain frames of data responsive to the varied elevation beam pattern.

Abstract: Sidelobe levels of bipolar and unipolar waveforms are suppressed. Bipolar and unipolar transmit waveforms are generated with a coded excitation, such as a chirp coding, and pulse width modulation. For harmonic, such as second harmonic, imaging, the fundamental transmit frequency of the transmit waveform is centered at a lower end of the bandwidth of the transducer. The transducer filters higher frequency components of the transmit waveform differently than lower frequency components. To generate the desired acoustic waveform, the transmit waveform generated for application to the transducer is adjusted to account for the frequency response of the transducer. For example, higher frequency parts of a chirp waveform has more pulse width modulation or narrower pulse widths to account for lesser magnitude reductions. Multiple transmit waveforms may be combined to reduce sidelobes for fundamental or second harmonic imaging. Two coded excitation waveforms are generated.

Abstract: An ultrasound system includes a transmit/receive switch (502), at least one frequency band selection circuit (512), and a selection unit (511). The selection unit (511) is used to determine if the data being received are from tissue or contrast agent regions. Depending on which type of region the data are from, different signal processing techniques are applied to the data. For example for tissue regions, a harmonic filter can be applied to the signal. If the signals are from contrast agent flow regions, both the harmonic filter and a fundamental filter can be used.

Abstract: A region of interest (ROI) of a patient's body is repeatedly scanned using an ultrasound transducer array. Data sets representing an image property, such as intensity, from portions of the ROI are used to calculate a representation of the displacement profile within the ROI at different stress levels. From the displacement profile, a function of strain is also preferably calculated. According to one aspect of the invention, a data set representing an estimate of the elasticity profile within the ROI is color-coded and is displayed along with a B-mode display in a single, overlaid display. According to another aspect of the preferred embodiment of the invention, the display of elasticity is adaptively persisted as a function of, for example, a measure of image quality. The invention also provides an on-screen guide that indicates to a user a measure of quality of each of a series of estimated displacement data sets.

Abstract: A method and system for quantification of strain imaging is disclosed. The method and system comprises performing a motion analysis on the at least two regions of interest. The method and system further includes providing a strain estimate for each of the at least two regions of interest and comparing the strain estimates of each of the at least two regions to quantify the strain for the at least two regions of interest. A system and method in accordance with the present invention provides for strain quantification based on conventional B-mode images. Using this technique, the strain of regions of interest (ROI) defined by users can be determined and quantitative comparisons can be effectively made in real time. The strain quantification can be used to determine tissue's properties and can potentially be applied in breast imaging as well as cardiac imaging.

Abstract: An ultrasound system includes a transmit/receive switch (502), at least one frequency band selection circuit (512), and a selection unit (511). The selection unit (511) is used to determine if the data being received are from tissue or contrast agent regions. Depending on which type of region the data are from, different signal processing techniques are applied to the data. For example for tissue regions, a harmonic filter can be applied to the signal. If the signals are from contrast agent flow regions, both the harmonic filter and a fundamental filter can be used.

Abstract: A method of dynamically measuring parameters within a series of images using image processing is disclosed. A sequence of ultrasound images is generated by means of an ultrasound system. A user determines at least one region of interest within a first image. Then, at least one parameter for each region of interest is evaluated, e.g. the number of pixels exceeding a pre-defined intensity are counted. A new region of interest within a sequential image is searched within a search area around the predefined region of interest which best matches the region of interest. This is done for all images of a sequence whereby the new region of interest which best matches the region of interest of the previous image is used as a region of interest for the following image.

Abstract: An ultrasound system (50) estimates the speed of sound in the tissue (60) under examination. The ultrasound system obtains a series of test images (150) using different estimates of the speed of sound in the body tissue. For each image produced, the ultrasound system computes a function that is indicative of image quality for one or more regions of interest (152) in the test image. The image quality function exhibits a minimum or maximum when computed for a region of interest obtained at a speed of sound substantially equal to a true speed of sound in the tissue. The ultrasound system selects the test image having the minimum or maximum function value and obtains subsequent images of the tissue using the speed of sound used to obtain the test image selected.

Abstract: An ultrasound imaging system comprises a position location array adapted to be affixed to a surface layer of an imaging subject. The position location array comprises a plurality of electrodes disposed in a grid pattern within a flexible substrate. An imaging transducer having at least one element is operable to provide an acoustic pulse through the position location array and the surface layer in response to a driving signal and to provide a corresponding return signal in response thereto. A receiver is coupled to the imaging transducer to receive the return signal from the at least one element and provide a beamformed signal. A processor coupled to the receiver and the position location array forms an image from the beamformed signal that includes position coordinates that correspond to an intersection between the acoustic pulse and associated ones of the plurality of electrodes.

Abstract: Counts of a gamma camera, acquired during a nuclear cardiac structure examination, which represent time-activity curves at different locations of a pixel matrix of the cardiac structure are fitted to a cosine wave function. From said fitted function the wave amplitude, phase, and an error value (representing the reliability of the acquired time-activity curve) are extracted. Finally, for each location in the pixel matrix said extracted values are simultaneously displayed as they are acquired.