Abstract: An electrostatic transducer circuit and method of tuning the same, in which a balancing inductance is inserted into the electrostatic transducer circuit is described. The electrostatic transducer circuit generally includes transmit circuitry, receive circuitry and a capacitive electrostatic transducer. The balancing inductance is tuned to counteract the negative reactance of the capacitive electrostatic transducer at a desired operating frequency during the transmit mode. The balancing inductance is inserted into the transmit circuitry and is then isolated from the remaining parts of the electrostatic transducer circuit. Isolation is achieved by switching the electrostatic transducer circuit between transmit and receive modes of operation. Further, a receive circuit balancing reactance can also be included. The method provides a balancing inductance that is used to counteract negative reactance of the capacitive electrostatic transducer at a desired operating frequency during transmit mode.

Abstract: A method and apparatus for apodization is exemplified in an ultrasound transducer used, for example, in medical applications. The method and apparatus of the present invention provides an ultrasonic transducer with frequency and amplitude apodization, thus improving signal quality and producing improved ultrasonic images. The manufacture of this apparatus is improved by the making of composite cuts into piezoelectric material according to a predetermined pattern which generally varies the concentration of piezoelectric material across the surface of the transducer. Concentration of piezoelectric material can be varied across the surface of the piezoelectric transducer by varying the spacing between the cuts in the piezoelectric material, or by varying the width of the cuts in the piezoelectric material, or a combination of both.

Abstract: A method and system are disclosed for recognizing tissue types. Electrical signals are applied to tissue 120 via electrodes 110, 112. Circuitry 106 and the signal processor 116 are used to measure impedance magnitude and phase at a plurality of frequencies. At least the phase information at the plurality of frequencies is compared with phase information of known tissue types. Based on the comparison, the tissue 120 may be assigned to one of the known tissue types.

Abstract: A dual pointing device to be used in cooperation with an imaging apparatus, a tracking system, and an object to be imaged. The dual pointing device provides a means for tracking a point on in image in both the image's frame of reference and Euclidean absolute coordinates. This is accomplished by having two tracking systems follow the dual pointing device. Since the two tracking systems follow the same physical device, and since one tracking system operates in the image coordinates while the other tracking system operates in the absolute coordinates, the device makes it possible to effect automatic transformations between the two systems. More specifically, in the preferred embodiment of the dual pointing device, which is intended for use with a magnetic resonance imager, the absolute tracking system is based on infra-red reflectors on the device that are tracked by an infrared transponder.

Abstract: The two-dimensional velocity vector using a pulsed ultrasound field can be determined with the invention. The method uses a focused ultrasound field along the velocity direction for probing the moving medium under investigation. Several pulses are emitted and the focused received fields along the velocity direction are cross-correlated. The time shift between received signals is found from the peak in the cross-correlation function and the velocity is thereby determined.

Abstract: An adaptive transmit-focusing and beam-forming method and apparatus is provided, which in connection with beam-forming applies adaptive patterns of delay profiles to reflected ultrasonic pulses from a group of ultrasonic pulses, received by transducer arrays, forms multiple sets of preliminary scan-line data, and combines the multiple sets of preliminary scan-line data into single scan-line data; and in connection with transmit-focusing performs focusing a group of ultrasonic pulses by applying a plurality of delay profiles in accordance with propagation velocities within an object region to be ultrasonic imaged. The adaptive transmit-focusing and beam-forming method and apparatus reduces transmit-focusing and beam-forming errors generated from applying a single pattern of delay profile, and provides clear ultrasonic images.

Abstract: A probe device is presented for use in an ultrasound-based measurement device for blood flow measurements in a patient's body. The probe comprises a housing containing a transducer arrangement. An outer surface of the housing, by which the probe is brought to a measurement location in the patient's body, is patterned so as to have at least one projecting portion. The design of the probe enables correct orientation of the transducers with respect to a blood vessel under measurements. The probe device is associated with an operation means for operating the probe, and an indication means for generating output data indicative of measurement results, which are incorporated in a common housing of a hand-held measurement device.

Abstract: A beamformer for an ultrasound imaging system is provided, the ultrasound imaging system having a probe having a transducer array for transmitting and receiving analog signals, and a personal computer. The beamformer includes a beamformer software application module configured for execution by the computing device for performing at least partial beamforming processing on digital data transmitted between the transducer array and the computing device, and means for exchanging signals and data between the transducer array and the computing device and performing at least one of A/D and D/A conversions on the exchanged signals and data. In the preferred embodiment, the beamformer further includes a module integrated within architecture of the computing device, wherein the integrated module is preferably Random Access Memory (RAM) included in storage means of the computing device.

Abstract: Connector and guidewires connectable thereto are disclosed which enable for the connection of guidewires requiring electrical connection to an external electrical source. These guidewires may be used for MRI imaging and the external source could be an MRI scanner. An embodiment of a guidewire is provided with enables for easier connection through improved dimensions and mechanical strength at the proximal end. An embodiment of a connector is provided which can attach to any guidewire or coaxial cable. These connectors provide for desirable mechanical and electrical properties while still enabling catheters and other tools to be used in conjunction with guidewires and other cables.

Abstract: An intravascular catheter system has a balloon angioplasty device disposed about a common lumen near its distal end. The common lumen is in communication with multiple lumens within a proximal region of the catheter body to allow for positioning of the catheter over a movable guide wire and convenient delivery of imaging or interventional devices to a desired region of the blood vessel being treated.

Abstract: An ultrasound catheter suitable for insertion in the body lumens of a patient during medical procedures is provided. An ultrasound transducer may be provided at the distal tip of the catheter. An inflatable balloon may be provided at the distal end of the catheter on the proximal side of the ultrasound transducer. The catheter may have lumens for inflation fluid, electrical wires, and a guide wire. A sheath that runs through the balloon may be used to isolate the electrical wires and guide wire from inflation fluid in the interior of the balloon.

Abstract: An optical detection type ultrasonic receiving apparatus in which S/N ratio of the detection signal is increased while preventing the apparatus from increase of size and cost. The ultrasonic receiving apparatus includes a light source for generating broadband light, an ultrasonic detecting element including an ultrasonic sensing portion to perform intensity modulation of the light, a spectrum-separating unit for spectrum-separating the modulated light, a photo detecting unit having a plurality of photoelectric converting elements for detecting the spectrum-separated light for each of plural wavelength components to generate at least a first detection signal of a first wavelength component and a second detection signal of a second wavelength component, and processing unit for carrying out processing operation using the first detection signal and the second detection signal to obtain information about the ultrasonic wave received by the ultrasonic detecting element.

Abstract: An ultrasonic apparatus and method are described in which a volumetric region of the body is imaged by biplane images. One biplane image has a fixed planar orientation to the transducer, and the plane of the other biplane image can be varied in relation to the fixed reference image. In a preferred embodiment one image can be rotated relative to the other, and can be tilted relative to the other. An image orientation icon is shown on the display screen together with the two biplane images depicting the relative orientation of the two planar images.

Abstract: In order to arrange continuous wave signal paths using fewer switches, a plurality of amplifying circuits 602 for respectively amplifying a plurality of continuous wave input signals, and outputting each respective pair of amplified signals that have mutually opposite phases for each continuous wave input signal; a plurality of selecting circuits 604, each of which selects one signal of the pair of amplified signals from each of the plurality of amplifying circuits; and a matrix switch 608 employing the output signals from the plurality of selecting circuits as input signals are provided.

Abstract: A phased array ultrasound scanning apparatus includes a one-dimensional (1-D) array of ultrasound transducer elements having transmit and receive elements. The 1-D array is responsive to a transmitter configured to energize the transmit elements for generating a transmit acoustic beam directed into a region of interest. A receive beamformer, operatively connected to the 1-D array, synthesizes receive beams, in response to echoes of the transmit acoustic beam received from the region of interest. The receive beamformer includes analog random access memory (ARAM) delay elements configured to delay signals received from the receive elements and provide the delayed signals on an output of the receive beamformer as a beamformed RF output. The beamformed RF output is suitable for use in forming an image of the region of interest.

Abstract: A method including positioning a catheter at a location in a blood vessel; imaging a thickness of a portion of a wall of the blood vessel at the location; identifying a treatment site; advancing a needle a distance into the wall of the blood vessel to the treatment site; and introducing a treatment agent through the needle to the treatment site. A composition including an inflammation-inducing agent and a carrier in the form of microspheres having a particle size suitable for transvascular delivery. A composition including a therapeutic angiogenesis promoter in a carrier and an opsonin-inhibitor coupled to the carrier. An apparatus for delivery of a therapeutic angiogenesis promoter.

Abstract: An acoustically generated image includes only selected acoustical components. When an original acoustic signal interacts with an object, the resultant acoustic signal comprises a diffracted component and an undiffracted component. The acoustical images of the present invention are generated with either the diffracted component only or the undiffracted component only. In an alternative embodiment, the acoustically generated image may comprise selected frequency component(s) from the diffracted component of the acoustic signal.

Abstract: Method and apparatus for 3D/4D ultrasonic imaging. An array of ultrasonic sources and receivers (7) positioned over or near tissue (6) transmit short encoded omnidirectional ultrasonic shots (9). The amplitude and phase of the resulting reflected waves (10) are detected, sampled and digitised. Traces from each shot are reconstructed by digital data processing. A three dimensional data volume is constructed corresponding to reflection amplitude through a regular volume. The data volume may then be imaged through any arbitrary plane. Time varying images can be readily produced as the process takes only a fraction of a second.

Abstract: Alcohol is used as a coupling medium between an ultrasonic transducer and patient skin providing rapid settling of quantitative measurements.

Abstract: A guiding catheter includes a Doppler sensor disposed at a distal end of a flexible shaft. The Doppler sensor can sense a blood flow turbulence level within a chamber of the heart or a blood vessel of the heart. Detecting changes in a blood flow turbulence level is used to assist guiding of the distal end of the flexible shaft. The Doppler sensor may include a piezoelectric sensor or an optical sensor. The sensor readings may be processed to show turbulence through a time domain or frequency domain presentation of velocity. The sensor readings can be used to modulate an audible waveform to indicate turbulence. The guiding catheter may further include steering apparatus enabling deflection of the distal tip.