Abstract: Highly specific measurements of flow in vessels, such as the coronary artery, can be obtained by processing cubic fundamental information. By showing flow in vessels with a high degree of contrast-to-tissue specificity, ultrasound based 3D contrast agent based coronary artery angiograms may be possible. Measurement and display of the velocity of agent from the cubic fundamental signal is provided simultaneously with display of cubic fundamental energy, such as providing a display map indexed by both energy and velocity. High pulse repetition frequency (PRF) for cubic fundamental detection in conjunction with long velocity measurement intervals may increase low velocity sensitivity and measurement precision. Pulsed wave (PW) Doppler may be improved by using a cubic fundamental sensitive pulse sequence.

Abstract: Automated determination and setting of an ultrasound system transmit power level is provided for contrast agent imaging. Low mechanical index imaging of contrast agents allows substantially continuous imaging of contrast agents without destruction. By comparing data associated with different transmit power levels, different delays between acquisition or different acquisition sequences, a contrast agent imaging transmit power generally minimizing destruction of contrast agents and maximizing signal-to-noise ratio is automatically determined.

Abstract: The gain for multiple mode imaging and/or contrast agent imaging is automatically adjusted. The gain algorithm separately determines gain parameters for two different types of imaging, such as tissue and contrast agent imaging. The gain based on the contrast agent image may be optimized to provide maximum sensitivity, such as by mapping noise values measured prior to injection of contrast agent to low values within the dynamic range or somewhat below the display dynamic range. The automatic gain based on the contrast agent image may be free of variance calculations. One of the two gain parameters is selected as the system gain, or the two gain parameters are combined to form the system gain. The presence of contrast agents within the image may be determined, and different gain parameters used based on the presence or absence of contrast agents. Various ones or combinations of the gain adjustments summarized above may be used.

Abstract: The gain for multiple mode imaging and/or contrast agent imaging is automatically adjusted. The gain algorithm separately determines gain parameters for two different types of imaging, such as tissue and contrast agent imaging. The gain based on the contrast agent image may be optimized to provide maximum sensitivity, such as by mapping noise values measured prior to injection of contrast agent to low values within the dynamic range or somewhat below the display dynamic range. The automatic gain based on the contrast agent image may be free of variance calculations. One of the two gain parameters is selected as the system gain, or the two gain parameters are combined to form the system gain. The presence of contrast agents within the image may be determined, and different gain parameters used based on the presence or absence of contrast agents. Various ones or combinations of the gain adjustments summarized above may be used.

Abstract: Methods and systems for detecting contrast agents is provided. Differences between different sized vessels throughout a period of contrast agent enhancement are identified without significantly depleting the available contrast agent. Dual detection paths are used for imaging, such as one path for detecting nonlinear response and another path for detecting differences between the responses to two or more pulses. Where echoes from two or more pulses of acoustic energy are combined to detect the nonlinear response, the nonlinear response may also include signals originating from a loss-of-correlation (LOC) or motion between received pulses. These signals generated from LOC or motion can be produced from agent disruption where a second received echo is different from a first received echo due to a change in a bubble's shape (i.e., destruction), or from simple spatial translation between acoustic pulses as seen from the same spatial location, respectively.

Abstract: A medical ultrasound imaging pulse transmission method transmits at least three pulses, including at least two pulses of different amplitude and at least two pulses of differing phase. The larger-amplitude pulse is transmitted with a larger aperture and the smaller-amplitude pulses are transmitted with respective smaller subapertures. The subapertures are arranged such that the sum of the subapertures used for the smaller-amplitude pulses is equal to the aperture used for the larger-amplitude pulse. In this way, pulses of differing amplitudes are obtained without varying the power level of individual transducer elements, and precise control over pulse amplitude is provided.

Abstract: A pulse echo beamforming system generates high spatial bandwidth ultrasound images using only a few transmit/receive events per frame. Each transmit/receive event consists of firing an unfocused or weakly focused wave and receiving and storing the echo on every receive channel. Each set of stored echoes is delayed and apodized to form component beams for each desired image point in the region insonified by that particular wave. The final images are synthesized by adding two or more of the component beams for each image point.

Abstract: A medical ultrasonic imaging method uses transmitted plane waves, or transmitted wavefronts that are substantially planar, to improve contrast agent imaging by generating peak pressures that are more uniform over depth. Depending on the type of contrast agent, the returned frequencies of interest, and the desired strength of the non-linear response, multiple wavefronts can be generated at substantially the same time to increase peak pressures.

Abstract: A medical ultrasonic imaging system transmits a set of two or more substantially identical transmit pulses into a tissue containing a contrast agent. The associated received pulses are filtered with a broadband filter that passes both the fundamental and at least one harmonic component of the echoes. The filtered received pulses are then applied to a clutter filter that suppresses harmonic and fundamental responses from slowly moving and stationary tissue, while clearly showing contrast agent response due to the loss of correlation effect. The disclosed system includes other signal paths for generating conventional B-mode images as well as combined images that include both components from the contrast-specific image as well as components from the B-mode image. An improved user interface allows the user to switch among these three images.

Abstract: An improved method for suppressing fundamental or desired harmonic orders in an ultrasonic medical imaging system transmits at least one reverberation-suppression pulse prior to the transmission of a multiple-pulse sequence. Receive signals associated with the pulses of the multiple-pulse sequence are acquired and combined using receive weights selected to suppress energy at either the fundamental or a desired harmonic of the fundamental.

Abstract: A method and system for flow or movement detection is provided. More than one clutter filter is used. Each clutter filter's magnitude versus frequency response is optimized differently. Estimates of the flow or movement are generated from the data output by each of the clutter filters. Using selection or combination of the resulting estimates, the best attributes of each filter are used for imaging.

Abstract: A system and methods for measuring the volume flow of fluid in an enclosed structure with an ultrasound system is provided. Manual designation of flow angles and areas may not be necessary. Velocities along two or more different scan lines in a first scan plane are obtained to determine an angle of flow within the enclosed structure. A Doppler spectrum parameter is measured from a transmission in a second scan plane substantially perpendicular to the first scan plane. Volume flow is calculated from the flow angle and the parameter. The scan planes are associated with rotating a linear array transducer or holding a multi-dimensional transducer in place. A C-scan method with a linear transducer may also be used.

Abstract: An ultrasonic imaging system that reduces image flashes by selectively replacing imaging parameters with corresponding imaging parameters from prior time sequences. Imaging parameters include filtered energy, unfiltered energy, variance, acceleration, velocity, and detected echo magnitude. Imaging parameters in several consecutive time sequences can be replaced with the same prior imaging parameter value until the flash is no longer detected. Spatial averaging can be used to improve detection and suppression of image flashes.

Abstract: A method and system for detecting energy using pulse inversion and Doppler processing are provided. Pulse inversion may be used to image the harmonic response of tissue alone or with contrast agents. Lowpass or bandpass clutter filters suppress the harmonic and/or fundamental response of tissue clutter to provide improvements in imaging, such as for imaging small vessels. Elimination of tissue clutter from both the fundamental components and second harmonic components in the Doppler domain increases the specificity of contrast agent and/or tissue.

Abstract: A method and system for Doppler processing of information at two or more different frequency bands for improved accuracy is provided. Signals from two or more unique frequency bands are processed separately to detect motion. Using signals at different frequency bands allows for more effective use of unused bandwidth to increase information content and improve estimation accuracy. One of or more of the two or more receive frequency bands may be within the transmitted fundamental frequency band or within harmonic frequency bands of the transmitted fundamental frequency band. The increased information content generated by using two separate narrow receive frequency bands is used to improve many aspects of motion detection. The resulting Doppler values of each parameter, such as velocity, energy, and variance parameters, are averaged or otherwise combined. One of the average, the Doppler values at each frequency band and a null value are selected for further processing and display.

Abstract: In an ultrasound system and method, a transducer connects to an estimator for obtaining first and second blood flow parameters associated with first and second scan line directions, respectively, in a first scan plane. One beam substantially covering a cross-sectional area of a tubular structure (uniform insonification) or a plurality of beams may be used. A first area associated with the cross-section of the tubular structure is also estimated from the blood flow parameters. The process is repeated for a plurality of scan planes. A processor determines the cross-sectional area of the tubular structure perpendicular to its axis (a second area), the average velocity of flow parallel to the axis, and the volume flow as a function of the first area and the first and second blood flow parameters of all the scan planes. For real-time volume flow, the orientation of the tubular structure is determined using the second area and the first and second blood flow parameters.

Abstract: In an ultrasound system and method, a transducer connects to an estimator for obtaining first and second blood flow parameters associated with first and second scan line directions, respectively, in a first scan plane. One beam substantially covering a cross-sectional area of a tubular structure (uniform insonification) or a plurality of beams may be used. A first area associated with the cross-section of the tubular structure is also estimated from the blood flow parameters. The process is repeated for a plurality of scan planes. A processor determines the cross-sectional area of the tubular structure perpendicular to its axis (a second area), the average velocity of flow parallel to the axis, and the volume flow as a function of the first area and the first and second blood flow parameters of all the scan planes. For real-time volume flow, the orientation of the tubular structure is determined using the second area and the first and second blood flow parameters.

Abstract: An ultrasonic diagnostic apparatus and method for real-time multi-dimensional blood flow imaging with enhanced sensitivity to lateral blood flow. The apparatus constitutes an improvement on the ultrasonic diagnostic apparatus of the type wherein an ultrasonic pulse beam is repeatedly transmitted into the subject under examination at a fixed pulse rate and the reflected echoes are picked up, amplified and displayed. The improvement comprises an ultrasonic transducer means comprising a phased array transducer which is electronically and/or mechanically divided into two or more independently controlled sub-apertures and adapted for transmitting ultrasonic pulse beams from one of the two or more sub-apertures and for receiving the reflected echoes with at least two of the two or more sub-apertures.