Abstract: A method and system for contrast agent imaging with a catheter transducer is provided. The catheter transducer may comprise an intra-vascular, intra-cardiac or other transducer for insertion into or through a small space. The catheter transducer is inserted within the heart or other portion of a patient. Contrast agents, such as micro-spheres, are injected into the patient. Using the catheter transducer, ultrasonic acoustic energy is transmitted, and reflected energy is received. The reflected energy is responsive to the contrast agents. An image processor generates an image of the tissue and contrast agents as a function of the reflected energy. The image provides an indication of perfusion. Alternatively, the ultrasound system calculates perfusion. By generating intra-vascular images or data, interference from other tissues is avoided. Therefore, the perfusion information obtained may have higher resolution. Images with better resolution better assist doctors in medical diagnosis.

Abstract: A method and system for obtaining ultrasound data with a sparse array of transducer elements is provided. About one wavelength of a highest operating frequency separates the center of each transducer element from any adjacent transducer element. While this spacing may generate grating lobes, the beamformer of the ultrasound system is configured to filter and isolate information at a harmonic of a fundamental transmit frequency. The resultant two-way beam pattern is less effected by the grating lobes. The image generated as a function of the harmonic information has few artifacts created as a function of the sparse spacing of the transducer elements. Given a set number of beamformer transmit channels, the sparse spacing may allow for a larger aperture width with few artifacts as a result of sparse element spacing. The larger aperture width generates a narrower beam in the azimuthal dimension of a one-dimensional transducer. By generating a narrower beam, better azimuthal resolution may be obtained.

Abstract: There is provided a transducer array with a plurality of piezoelectric elements having a minimum and maximum thickness. In one embodiment, the maximum thickness is less than or equal to 140 percent of the minimum thickness. In an alternate embodiment, the maximum thickness is greater than 140 percent of the minimum thickness and the transducer array is capable of simulating the excitation of a wider aperture two-dimensional transducer array. One or more matching layers may be used to further increase bandwidth performance. In addition, a two crystal transducer element as well as a composite transducer structure may be formed using the principles of this invention.

Abstract: There is provided a transducer array with a plurality of piezoelectric elements having a minimum and maximum thickness. In one embodiment, the maximum thickness is less than or equal to 140 percent of the minimum thickness. In an alternate embodiment, the maximum thickness is greater than 140 percent of the minimum thickness and the transducer array is capable of simulating the excitation of a wider aperture two-dimensional transducer array. One or more matching layers may be used to further increase bandwidth performance. In addition, a two crystal transducer element as well as a composite transducer structure may be formed using the principles of this invention.

Abstract: The invention provides a method and system for adaptive persistence processing in an ultrasound imaging system. Acoustic signals are temporally filtered using an adaptive persistence filter, having a recursive stage followed by a nonrecursive stage. A set of filtering coefficients for each stage are supplied by a look-up table in a memory, addressed or indexed in response to a plurality of input or output pixel values. The look-up table may therefore embody any selected function of its input variables. The input variables for the look-up table function are a current input pixel value X.sub.n and a previous intermediate pixel value W.sub.n-1, and the function embodied by the look-up table includes a relative first difference function for selecting a filter coefficient. A recursive filtering coefficient .alpha. is held constant over time, while a nonrecursive filtering coefficient .gamma. is adjusted dynamically in response to the current input pixel value X.sub.n and the previous intermediate pixel value W.

Abstract: There is provided a transducer array with a plurality of piezoelectric elements having a minimum and maximum thickness. In one embodiment, the maximum thickness is less than or equal to 140 percent of the minimum thickness. In an alternate embodiment, the maximum thickness is greater than 140 percent of the minimum thickness and the transducer array is capable of simulating the excitation of a wider aperture two-dimensional transducer array. One or more matching layers may be used to further increase bandwidth performance. In addition, a two crystal transducer element as well as a composite transducer structure may be formed using the principles of this invention.

Abstract: An ultrasound transducer assembly having a housing, a transducer array mounted in the housing, and active cooling mechanism positioned adjacent to the transducer array for actively removing heat generated by the array by transport of heat energy from the affected site. The active cooling mechanism may comprise a heat exchanger including a closed loop circulating coolant system circulating coolant, or a single-pass flowed coolant, passing through the heat exchanger, a heat pipe, a thermoelectric cooler, an evaporative/condenser system, and/or a phase change material. One or more heat exchangers may be used having gas or liquid coolants flowing therethrough. The heat exchangers and coolant pumps may be located in various components of the transducer assembly, including the array housing, the connector assemblies or the ultrasound console.

Abstract: There is provided a transducer array with a plurality of piezoelectric elements having a minimum and maximum thickness. In one embodiment, the maximum thickness is less than or equal to 140 percent of the minimum thickness. In an alternate embodiment, the maximum thickness is greater than 140 percent of the minimum thickness and the transducer array is capable of simulating the excitation of a wider aperture two-dimensional transducer array. One or more matching layers may be used to further increase bandwidth performance. In addition, a two crystal transducer element as well as a composite transducer structure may be formed using the principles of this invention.

Abstract: Obstructions in a blood vessel are identified and displayed by determining changes in textural patterns based on the ultrasonic waves reflected from the blood vessel. The textural pattern from stationary scatterers, such as found in a clot, remains essentially constant, whereas the texture pattern for moving scatterers such as flowing blood cells is ever changing. By determining and imaging the variations in textural pattern of the reflected ultrasonic waves the identification of obstructions in the vessel is realized.

Abstract: A pair of electrical cables to be interconnected, each have an outer layer of insulation and a central conductor terminating in a cable end. A generally funnel shaped conductor is attached to the conductors of each cable end forming a concave terminal on each cable end. A spherical conductor is interposed between the funnel shaped conductors of the cable ends. The cable ends and the spherical conductor are compressively engaged to provide assured electrical contact through the cables and are enclosed within a tubular dielectric housing. The cable ends extend through apertures in threaded end plugs and into the tubular housing. The housing includes a dielectric grease to displace all air within the housing. A seal and tubular sleeve are interposed between the end plugs and the funnel shaped conductors of the cable ends so that threaded engagement of the end plugs provide axial compressive forces on the funnel shaped conductors and also seal the connection.

Abstract: Raster lines are obscured in a photograph of an image displayed on a video monitor. A photographic film is used as an integrating mechanism. The TV raster is vertically displaced during the camera shutter open time a total deflection of one horizontal line, thus blending the information between horizontal lines. Vertical raster deflection is accomplished by adding a series of delays to the normal vertical sync and then generating a processed composite sync to drive the external sync input to the monitor. The shutter is open for several video frames, each frame being deflected vertically by an integer amount greater than the previous frame until the total raster deflection equals one horizontal line.