Abstract: The present invention is directed to a device for visualizing structure located on the interior of a biological substance. The device of the present invention includes a marker member which may be a solid cylinder or lumen having an interior volume. The marker member has a proximal end, and a distal end. The distal end of the device is removably insertable in the biological substance relative to the interior structure to be visualized and is composed of a biologically stable substrate material. An image-enhancing material is contained relative to the marker member in a manner such that the imaging material does not directly contact the biological substance; such imaging material will remain self-contained without causing significant tissue absorption, toxicity or undesired image distortion. The imaging material of choice is one which is capable of producing an emission or signal detectable external to the biological substance by suitable imaging instrumentation.

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: An ultrasonic diagnosis apparatus and method wherein both imaging of a contrast effect and imaging of a tissue appearance before and after inflow of a contrast medium can be realized on condition that low-power transmission and a high frame rate are maintained. The ultrasonic diagnostic apparatus includes a transmission/reception unit for transmitting subject ultrasonic waves with a band substantially centered at a fundamental frequency and generating a received signal based on an ultrasonic echo from the subject, a harmonic unit for extracting a signal of a harmonic component of the fundamental frequency included in the received signal and extracting a signal of the fundamental component with the band substantially centered the fundamental frequency included in the received signal, and a display unit for generating a display image based on the extracted harmonic and fundamental components.

Abstract: An ultrasonic diagnostic imaging system and method are presented to determine low rates of blood flow using contrast agents. Pairs of differently modulated pulses are transmitted in several beam directions to acquire echoes which can be combined to separate harmonic frequencies by pulse inversion. The pulses of each pair are transmitted in rapid succession to minimize motional artifacts. The transmission in the different beam directions is time-interleaved, resulting in the sampling of each beam direction over a long ensemble time for the detection of low rates of flow.

Abstract: New contrast agents for ultrasound imaging and methods for use of such agents for imaging of human or animal tissue are described, wherein a primary active component of such medicaments is a halogenated xanthene or halogenated xanthene derivative. Preferably, the halogenated xanthene is Rose Bengal or a functional derivative of Rose Bengal.

Abstract: Ultrasonic imaging to receive a signal from contrast agent microbubbles in arterioles of a myocardium, without being masked by a signal from microbubbles in capillaries of the myocardium. For example, high power ultrasonic energy is emitted to destroy microbubbles in the arterioles and capillaries. A time delay passes from the destruction. The time delay is sufficiently long to allow the arterioles to refill with microbubbles and sufficiently short so that the capillaries do not completely refill with microbubbles. Ultrasonic imaging is then performed to receive a signal between harmonics from the microbubbles refilled in the arterioles. Various other destructive and non-destructive imaging techniques are disclosed.

Abstract: Coatings to enhance the echogenicity of materials are especially useful for medical devices wherein the practitioner desires to locate or visualize a device by ultrasonic imaging when the device is inserted into a body cavity. These coatings can be applied to any device of virtually any composition. To accomplish this, a polymer matrix is formed containing an entrapped gas in enclosed bubbles or open surface channels or cavities. Coated needles are visible in ultrasound when inserted in animals. A pre-coat or base coat may be applied to condition the surface to enhance adhesion. A finish coat or top coat may be applied to improve durability, smoothness, and biocompatibility, lubricity, antibiotic, antimicrobial, antithrombogenic activity, and other desirable properties for the finished product. Coating liquids and methods for preparing and applying such coatings are disclosed, including forming bubbles by chemical reaction during the coating process.

Abstract: (n−1) frames of image information which rarely includes contrast agent information are subtracted from addition information obtained by adding a multi-shot image group consisting of a plurality of frames (for example, n−1 frames) which includes the contrast agent information, thereby acquiring image information based on all of the contrast agent which has existed in one scanning plane in the image processing manner.

Abstract: Ultrasound imaging using gas microbubble-containing contrast agents may be performed in the recirculating phase following admixture of the contrast agent with the blood pool, thereby prolonging the useful imaging time window compared to that conventionally obtained during the backscatter signal peak resulting from first pass of a contrast agent bolus. The length of the time window may further be increased by imaging at ultrasound frequencies of 2 MHz or less, particularly by harmonic imaging at transmit frequencies less than the resonance frequencies of the gas microbubbles.

Abstract: In order to properly discern a plurality of streams of blood flow having different contrast agent arrival times or blood concentration properties, an ultrasonic diagnostic apparatus 200 comprises: an ultrasonic probe 1; a transceiver section 2; a quadrature detector section 3; a power calculating section 4 for calculating the power P of blood flow; a power peak holding section 21 for comparing the latest power P and a predecessor peak value Po, and outputting the larger one as a peak value P′ and an elapsed time t′ corresponding to the peak value P′; a predecessor power/elapsed time keeping section 22 for keeping the predecessor peak value Po and the corresponding elapsed time ‘to’ and outputting these values to the power peak holding section 21; a timer 11 for measuring an elapsed time t from a reference time; a blood flow image producing section 25 for producing a power peak hold blood flow image G2 in which the hue is changed before and after the elapsed time t′ reaches

Abstract: A method and system for displaying a parametric image showing tissue perfusion includes an ultrasonic imaging system coupled to an ECG device. The ECG device triggers the imaging system to obtain contrast image data showing tissue perfusion at a respective predetermined time during each of a plurality of heartbeats. Parametric image data for discrete locations in the area of interest such as the myocardium is determined from the temporal contrast data acquired during reperfusion of the tissue in the area of interest. The parameters are mapped to a display value such as color to produce a parametric perfusion ultrasound image. Sequences of images may be produced which depict both perfusion characteristics and dynamic wall motion of the myocardium in a common image sequence.

Abstract: A system and a method for adjusting contrast and brightness in an image, e.g., an ultrasound image. The contrast and brightness are adjusted by processing global pixel intensity data to form a set of data representing a histogram. An algorithm is then employed to filter the pixel intensity values as a function of certain characteristics of the histogram data. The algorithm is designed to enhance contrast and brightness without affecting the near-field region in the ultrasound image. The filtering operations may be performed by a dedicated processor or by a fast general-purpose computer.

Abstract: Described herein is an ultrasound probe for ultrasound imaging using contrast enhancing agents and including two interleaved arrays of transducer elements. Each array has a longitudinal dimension along which transducer elements are placed. One interleaved array includes transducer elements having a lower center frequency. Another interleaved array includes transducer elements having a higher center frequency. The transducer elements are provided on inter-fitting support members. A length of the transducer elements of one array is larger than a corresponding length of the transducer elements of the other array.

Abstract: Apparatus and methods are disclosed for the detection and imaging of ultrasonic contrast agents. Ultrasonic apparatus is provided for coherent imaging of ultrasonic contrast agents, and for detecting harmonic contrast agents. The inventive apparatus includes a dual display for simultaneously viewing a real time image which displays the location of the contrast agent and a triggered contrast image. Methods of contrast agent detection and imaging include the measurement of perfusion rate characteristics, multizone contrast imaging, multifrequency contrast imaging, tissue perfusion display, and high PRF contrast image artifact elimination.

Abstract: A system and method for ultrasound imaging of breast tissue by injecting an ultrasound contrast agent into a duct lumen of a patient's breast to enhance the imaging of one or more ducts within a specified lobe of the breast to improve characterization of a lesion or lesions within the duct system of the specified lobe are disclosed. The ultrasound contrast agent used to improve breast imaging may be injected into the duct lumen through an orifice on the nipple and/or a duct wall into the duct lumen. The ultrasound contrast agent may be injected prior to and/or during ultrasound imaging. The ultrasound contrast agent may be an acoustically detectable gas such as a halogenated hydrocarbon, halogenated alkane gases, nitrogen, helium, argon and/or xenon. The halogenated alkane gas may be a perfluorinated hydrocarbon such as saturated perfluorocarbon, unsaturated perfluorocarbon, and/or cyclic perfluorocarbon. The acoustically detectable gas may alternatively be mixed in a liquid solution.

Abstract: A method of ultrasound imaging, including the following steps, transmitting ultrasonic beams generated by transducers (20) into an object volume (v) such as an object body or a part thereof, receiving (20) and storing (3) signals reflected from said object volume, processing and receiving signals into image data associated to image dots or lines of a video display (8), and displaying at least a few image data on the display (8) in accordance with parameters set by a user and related to a predetermined section or projection plane of the image of said object volume. According to the invention, scanning is only performed in the region of the object body which coincides with the section plane or the image projection plane (P) of the object volume along which imaging is to be performed.

Abstract: Microcapsules are prepared by a process comprising the steps of (i) spray-drying a solution or dispersion of a wall-forming material in order to obtain intermediate microcapsules and (ii) reducing the water-solubility of at least the outside of the intermediate microcapsules. Suitable wall-forming materials include proteins such as albumin and gelatin. The microcapsules have walls of 40-500 nm thick and are useful in ultrasonic imaging. The control of median size, size distribution and degree of insolubilization and cross-linking of the wall-forming material allows novel microsphere preparations to be produced.

Abstract: Ultrasound diagnosis apparatus includes a transceiver unit, an adding processor, a filter, and an image processor. The transceiver unit insonifies an object injected with a contrast agent via an ultrasound transmission signal transmitted at a fundamental frequency f0 with at least two transmission rates. The adding processor adds a first component of the ultrasound echo signal and second component of the ultrasound echo signal. The first component is transmitted at a first rate of the at least two transmission rates and the second component is transmitted at a second rate of the at least two transmission rates. The filter suppresses at least a first frequency band of an addition result that is centered about a frequency 2·f0. The image processor then generates image data based on a suppressing result.

Abstract: A method of enhancing the permeability of a biological membrane, including the skin or mucosa of an animal or the outer layer of a plant to a permeant is described utilizing microporation of selected depth and optionally one or more of sonic, electromagnetic, mechanical and thermal energy and a chemical enhancer. Microporation is accomplished to form a micropore of selected depth in the biological membrane and the porated site is contacted with the permeant. Additional permeation enhancement measures may be applied to the site to enhance both the flux rate of the permeant into the organism through the micropores as well as into targeted tissues within the organism.

Abstract: Methods and apparatus are provided for controlling fluid flow or perfusion, wherein gas-filled microbubbles are used as ultrasound contrast-enhancing agents, and wherein the method comprises separating the removal of the contrast agent due to flow from the removal of the contrast agent due to bubble destruction for enhanced imaging processes. By varying exposure of the microbubbles to ultrasound, the method and apparatus apply the changes observed in the images to measure flow and vascularity, to improve visualization of blood flow and blood vessels, and to guide delivery of drugs locally to the site of imaging.

Abstract: A method for ultrasound imaging in the presence of contrast agents, particularly in the field of cardiology, including detecting physiological, especially electrocardiographic signals; transforming the signals or a part thereof into pulses for controlling an ultrasonic probe pointed to the heart region, to synchronize it with the heart cycle; performing image acquisitions at predetermined heart cycle phases for predetermined limited times, with a predetermined ultrasonic beam intensity; processing the received signals and displaying them on a display. Image acquisition takes place in the systolic phase of each heart cycle from the end of diastole to the end of systole, a certain fixed number of acquisitions per unit time and an intensity of the ultrasonic beams being determined with the help of an intermediate Mechanical Index for controlled destruction of a certain percentage of contrast agent microbubbles.

Abstract: Methods and apparatus for producing zones with different contrast agent concentrations in a contrast agent infused target. An aspect of the method is subjecting the target to an ultrasound flash capable of producing first and second target zones, the first target zone having a higher concentration of contrast agent than the second target zone. Another aspect of the method is forming an ultrasound image of the target, wherein the first and second target zones in the ultrasound image have different ultrasonic responses. An embodiment of the apparatus of the present invention comprises a front-end controller (FEC) for use in a medical imaging system wherein the FEC controls a transducer to selectively radiate, in a single frame, a first beam position at a first energy and a second beam position at a second energy.

Abstract: An ultrasound imaging marker has a marker body that is constructed of an ultrasound resonant material and that includes a resonant pocket. The marker body includes an interior surface and preferably an angled surface. The resonant pocket provides a feature that is easily visible to the ultrasound device. The interior surface is preferably coated with a metallic resonant layer such as alumina or gold. The angled surface bounds the interior surface and connects the interior surface with the perimeter lip. The ultrasound imaging marker is preferably used in conjunction with an insertion device for inserting the ultrasound imaging marker adjacent the location.

Abstract: The present invention relates to methods to image the skin surface in order to view intercellular and intracellular structure. In particular, the invention relates to use of a compound (e.g., fluorescent dye) to enhance contrast and obtain better imaging.

Abstract: Nonlinear tissue or contrast agent effects are detected by combining echoes from multiple, differently modulated transmit pulses below the second harmonic band. The received echoes may even overlap the fundamental transmit frequency band. The modulation may be amplitude modulation or phase or polarity modulation, and is preferably both amplitude and phase or modulation. The present invention affords the ability to utilize a majority of the transducer passband for both transmission and reception, and to transmit pulses which are less destructive to microbubble contrast agents.

Abstract: Line synthesis avoids artifacts from differences in collateral destruction of contrast agent. Data representing a plurality of scan lines is received in response to each transmit event. Transmission and reception along the same scan lines are repeated a plurality of times for loss correlation imaging. Coherent data or data prior to detection along two or more scan lines is combined, removing differences. The combined data represents a synthesized line of data for detection. Line data representing contrast agents or not representing contrast agents may be synthesized from detected data. Detected data or data in the magnitude and phase domain representing two or more scan lines is combined. By altering the data provided to a flow processor or Doppler data detector, the relative phase of the data representing the two scan lines is determined. A magnitude for a synthetic line is calculated as a function of the magnitude of data representing two separate scan lines and the relative phase.

Abstract: The present invention relates to a method of contrast enhanced ultrasonic diagnostic imaging comprising administering to a subject a contrast enhancing amount of spherical particles comprising a matrix enclosing a gaseous contrast agent which reflects sound waves, said matrix being a biocompatible, biodegradable, non-immunogenic non-polyamino acid synthetic polymer; and generating an ultrasonic image of said subject. The polymer may be selected from the group consisting of carbohydrates, carbohydrate derivatives and non-polyamino acid synthetic polymers.

Abstract: An ultrasonic diagnostic apparatus for arranging functions, each of which configures a desired activity based on at least one of time information and operational information, and creating a technical flow protocol for defining work procedures in ultrasonic diagnosis is provided. Operation in scanning and in analysis processing of the ultrasonic diagnostic apparatus is controlled and executed in accordance with this technical flow protocol. In addition, in the case of reorganizing technical flow protocols in which a plurality of activities coexist, it is determined whether or not functions each configuring activities each is executable by administrating a contrast medium or medicine based on at least one of time information and operational information. In the case where it is determined that such each function is executable, a technical flow protocol is reorganized, and control in accordance with such protocol is carried out.

Abstract: An ultrasonic transducer, method, and system are disclosed for performing ultrasonic harmonic imaging in a medium or a living body. The ultrasonic transducer consists of a linear array of alternating long and short elements. A first set of transducer elements is for transmitting and receiving at a fundamental frequency, and a second set of transducer elements is for receiving second harmonic or subharmonic echoes, each set operating at their respective center frequencies. This dual-frequency ultrasonic transducer is coupled to an ultrasound system wherein transmit beamforming is done at the fundamental frequency, and receive beamforming is done at the second harmonic or subharmonic frequency. When receive beamforming at the fundamental frequency is added, the method enables parallel fundamental, harmonic, compound, and difference imaging.

Abstract: An ultrasonic image diagnostic apparatus measures an arbitrary elapsed time in an arbitrary time measuring circuit, and simultaneously displays this time information and an ultrasonic image on a monitor or stores the image and the elapsed time information in a storage section in correspondence with each other.

Abstract: Apparatus and methods are disclosed for the detection and imaging of ultrasonic contrast agents. Ultrasonic apparatus is provided for coherent imaging of ultrasonic contrast agents, and for detecting harmonic contrast agents. The inventive apparatus includes a dual display for simultaneously viewing a real time image which displays the location of the contrast agent and a triggered contrast image. Methods of contrast agent detection and imaging include the measurement of perfusion rate characteristics, multizone contrast imaging, multifrequency contrast imaging, tissue perfusion display, and high PRF contrast image artifact elimination.

Abstract: An ultrasonic diagnostic apparatus transmits ultrasonic pulses relevant to each scanning line twice, for example, while changing a center frequency of a bandwidth; acquires an electrical receiving signal that corresponds to an ultrasonic echo for such each transmission; applies filter processing with characteristics in accordance with a bandwidth of a harmonic component of a respective one of two receiving signals received for each scanning line; synthesizes the thus processed two receiving signals; and generates/displays an image by using the synthesized receiving signal. In this manner, the resolution and signal intensity in a depth direction is improved by broadening the bandwidth of a harmonic component provided for image generation, and a harmonic image having an occurrence of a motion artifact restrained is provided.

Abstract: A system and method for fundamental real-time imaging of the non-linear response of tissue perfused with a contrast agent are disclosed. An image with increased sensitivity to non-linear responses can be achieved by detecting the ultrasound response at the fundamental frequency from tissue perfused with a contrast agent and excited by multiple excitation levels. The responses detected from the multiple excitation levels may be gain corrected in an amount corresponding to the difference in magnitude of the excitation levels, then mathematically combined. The mathematical manipulation serves to remove linear responses to the fundamental excitation from the detected image. An ultrasonic contrast agent and tissue imaging system can be implemented with a transducer, first and second transmitters, a receiver, a control system, a processing system and a display.

Abstract: Quadrature demodulation apparatus and method for detecting a contrast agent in an ultrasonic echographic system, including an in phase/quadrature demodulator for determining the resolved complex real and imaginary in phase and quadrature components of return signals and a contrast agent detector determining the complex difference between first and second return signals. The detector is implemented as a magnitude of difference detector determining the magnitude of the complex difference of pairs of first and second return signals wherein the real and imaginary components of the return signals, including magnitude and phase information, are used to determine the magnitude of the complex difference between first and second return signals.

Abstract: A method for detecting the presence of contrast agent in the body of the patient initially transmits ultrasound pulses along respective acoustic scan lines, which pulses exhibit a fundamental transmission frequency. A set of returned signals are received along a respective scan line after each pulse transmission. The return signals are mathematically reconstructed to provide a first spectral component around the fundamental frequency and a second spectral component around a harmonic frequency. The peak amplitude of the reconstructed spectral components are compared to determine whether a contrast agent is present in the tissue, and hence to differentiate myocardium and perfused myocardium.

Abstract: The method of the invention controls an ultrasound system to image a microbubble contrast agent in a region of fluid flow and/or a region of tissue that is perfused by blood or other fluid. A transducer transmits ultrasound acoustic signals having a fundamental frequency f and receives echoes resulting from interaction of the ultrasound signals with both tissue and the microbubble contrast agent. A transmitter controls the transducer to transmit ultrasound signals at a sufficient power level to destroy the microbubble contrast agent. A receiver processes the echoes and selectively extracts signal components that exhibit a noninteger multiple of the fundamental frequency f of the transmitted acoustic signal. The system then produces images, principally from signal components including those that exhibit the noninteger multiple of the fundamental frequency f.

Abstract: An ultrasound system for continuous imaging and for controlling release of an encapsulated agent from a carrier comprises a housing secured to a patient's body, a transducer mounted within the housing, means for controlling the transducer to insonify the drug carrier with an ultrasonic signal and to thereby cause the release of the agent, and means for processing an ultrasonic echo signal to produce an image. Also, a method for controlling release of an encapsulated agent from a carrier comprises the steps of measuring a physiological parameter of a patient based on an ultrasonic echo signal, comparing the physiological parameter to a threshold, and transmitting an ultrasonic signal to insonify the carrier and thereby cause the release of the agent from the carrier in accord with the measured physiological parameter.

Abstract: A photographing cycle consisting of a weak ultrasonic monitor image photographing step of photographing monitor images by using a weak enough ultrasonic wave not to let the contrast agent disappear, a strong ultrasonic B mode image photographing step of photographing a B mode image by using a strong enough ultrasonic wave to make the contrast agent disappear, and a weak ultrasonic CFM image photographing step for photographing CFM images by using a weak enough ultrasonic wave not to let the contrast agent disappear is iterated. The latest image resulting from the addition of the CFM image is displayed superposed over the B mode image.

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: Methods and apparatus for enhancing the capabilities of ultrasonic techniques through use of ultraharmonics are provided.

Abstract: A method and apparatus for achieving ultrasonic coronary thrombolysis. After intravenous injection of a thrombus-specific ultrasound contrast agent, an array of ultrasonic transducers arranged in a pad placed on the patient's chest transmits ultrasound signals into the patient, from a virtual source. Reflected signals are then analyzed to determine the ratio of the second (or hall) harmonic to first harmonic components in the signals. A high ratio indicates the presence of a thrombus in the field of interrogation Time-of-flight data for each of the receivers is used to calculate a spatial location of the thrombus, and a phased array ultrasonic transmission is then focused on the thrombus, so as to achieve sonoparation.

Abstract: An ultrasonic diagnosis apparatus includes an ultrasonic probe. A transmitter supplies a transmission pulse to the ultrasonic probe to repeatedly transmit an ultrasonic wave to each of a plurality of scanning lines. A receiver receives echoes of the ultrasonic waves through the ultrasonic probe and obtaining a plurality of received signals for each of the plurality of scanning lines. A displacement estimating means estimates a relative change accompanying a tissue motion between received signals associated with each of scanning lines. A displacement correcting means corrects the received signals in accordance with the change detected by the displacement estimating means. A harmonic component extracting means extracts a harmonic component from the received signals corrected by the displacement correcting means. A display means generates an ultrasonic image on the basis of the harmonic component extracted by the harmonic component extracting means. A monitor displays the image generated by the display means.

Abstract: An ultrasound system that has transmit and receive circuitry that, pursuant to a plurality of image settings, transmits ultrasound signals into a patient, receives echoes from a patient and outputs a signal representative of the echo. Control circuitry is provided that sequentially adjusts the image settings so as to cause the transmit and receive circuitry to have a sequence of imaging configurations during an ultrasound imaging study. A memory may be provided that stores a plurality of state diagrams, each defining a sequence of imaging configurations for a particular imaging study, which are accessible by the control circuitry, wherein the control circuitry accesses a selected state diagram to conduct an imaging study. Such a system is particularly useful for imaging studies that utilize contrast agents.

Abstract: A PC board of a PC has a controller for controlling a motor drive circuit based on a timing signal, a memory for GAIN/STC for storing amplification data in an data in an amplifier for GAIN/STC as digital data and outputting the stored data synchronously with the timing signal of the controller, and a PC internal bus controller for connecting a PC internal bus to a local bus. Set values of GAIN and STC are converted into parameters and are set to the memory for GAIN/STC and a set value of contrast is converted into a parameter and is set to the controller both in a live state and in a freeze state.

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: A system and method for fundamental real-time imaging of the non-linear response of tissue perfused with a contrast agent are disclosed. An image with increased sensitivity to non-linear responses can be achieved by detecting the ultrasound response at the fundamental frequency from tissue perfused with a contrast agent and excited by multiple excitation levels. The responses detected from the multiple excitation levels may be gain corrected in an amount corresponding to the difference in magnitude of the excitation levels, then mathematically combined. The mathematical manipulation serves to remove linear responses to the fumdamental excitation from the detected image. An ultrasonic contrast agent and tissue imaging system can be implemented with a transducer, first and second transmitters, a receiver, a control system, a processing system and a display.

Abstract: A medical diagnostic ultrasound imaging method fires a sequence of pulses into a body and then receives, beamforms, weights and sums the resulting echo signals to suppress first order echoes. The sequence of pulses includes at least two pulses that differ in amplitude and phase. In one form, no two pulses of the sequence have the same amplitude and opposite phase. In another form, only linear echoes are suppressed. In a third form, second and third order echoes are preserved while linear echoes are suppressed.

Abstract: An ultrasonic diagnostic imaging system is described for performing nonlinear echo signal imaging with intermodulation product (sum or difference frequency) components. The system includes a digital transmitter which develops digital waveforms for two frequencies of a transmit beam. The digital waveforms are combined, converted to analog waveforms, and applied as transmit signals to the elements of a transducer array. In an alternate embodiment, a library of digital, multifrequency waveforms is maintained, from which a desired digital waveform is selected, converted to an analog waveform, and applied as transmit signals to the elements of a transducer array.

Abstract: A method and system for contrast agent image beamformation is provided. The acoustic energy of transmit beams is spread laterally to reduce contrast agent destruction. For example, a smaller aperture is provided for contrast agent imaging than for a default imaging mode. As another example, an apodization profile with a low amplitude for edge elements for contrast agent imaging is used as compared to the edge elements for a default imaging mode. As yet another example, the focal point used for contrast agent imaging is set to be outside of the region of interest (e.g. a shallow or deep focal point).

Abstract: Harmonic imaging using harmonic Golay-coded excitation that encodes the fundamental and second harmonic signals utilizes the transmit sequences encoded using QPSK implemented as quarter-cycle circular rotations or shifts of the base pulse. This is implemented by time shifting the chips of the transmit sequence encoded with a “j” or “−j” code symbol by ¼ fractional cycle at center frequency relative to the chips encoded with a “1” or “−1” code symbol. A different QPSK transmit code is used for each of four transmits A, B, C and D. The transmit codes are selected such that (A-B) and (C-D) are encoded by Y and −X, respectively, while (A2-B2) and (C2-D2) are encoded by X and Y, respectively, where X and Y form a Golay code pair. The coding and decoding technique achieves fundamental suppression and second harmonic compression for a given Golay code pair X and Y.