Dvx, LLC

Echocath Inc.

Catheter Technology Corporation

Ultra Med, Inc.

Catheter Technology Co.

Ecocath, Inc.

David Vilkomerson

Bayard G Gardineer

Thomas A Chilipka

Francis A Debernardis, Jr

John W Bogan

David Lyons

The velocity of fluids containing particles that scatter ultrasound can be measured by determining the Doppler shift of the ultrasound scattered by the particles in the fluid. Measuring fluid flow in cylindrical vessels such as blood vessels is an important use of Doppler ultrasound. This invention teaches using various configurations of cylindrical diffraction-grating transducers and cylindrical non-diffraction-grating transducers that suppress the Doppler shift from non-axial components of fluid velocity while being sensitive to the Doppler shift produced by axial velocity components. These configurations thus provide accurate measurement of the net flow down the vessel, even when the fluid flow is curved or not parallel to the vessel wall.

Flow measurement apparatus and method

Ultrasound diffraction-grating transducers produce beams at an angle to their face, which makes them useful for Doppler measurement of scattering fluids such as blood. The present invention discloses a diffraction-grating transducer, with the capability to focus transmitting or receiving beams to a desired point in space. This focusing capability leads to greater sensitivity when the diffraction-grating transducer is used as a receiver, and greater concentration of ultrasound energy when used as a transmitter. The focusing is achieved by using curved elements instead of the straight ones in conventional diffraction-grating transducers, and by using non-uniform spacing among these elements rather than the uniform spacing of conventional diffraction-grating transducers. Methods of computing the proper curvature of the elements and their spacing for a desired focal point in space are provided.

Focused ultrasonic diffraction-grating transducer

Matching layers improve the performance of ultrasonic transducers. Such layers have traditionally required significant effort and expense to be added to ultrasonic transducers. The present invention discloses a method of producing ultrasonic transducers with a matching layer, specifically for ultrasonic transducers utilizing piezopolymer transducer materials. Rather than the conventional method of forming the piezopolymer on a substrate and then attaching a matching layer through which the transducer emits its ultrasound energy, we teach depositing the piezopolymer on a substrate that also serves as a matching layer through which the ultrasound is emitted. We also teach depositing an additional shield layer for reducing electromagnetic interference. Methods of how to select materials and modify their ultrasonic characteristics are also discussed.

Process of manufacturing a piezopolymer transducer with matching layer

Matching layers improve the performance of ultrasonic transducers. Such layers have traditionally required significant effort and expense to be added to ultrasonic transducers. The present invention discloses a method of producing ultrasonic transducers with a matching layer, specifically for ultrasonic transducers utilizing piezopolymer transducer materials. Rather than the conventional method of forming the piezopolymer on a substrate and then attaching a matching layer through which the transducer emits its ultrasound energy, we teach depositing the piezopolymer on a substrate that also serves as a matching layer through which the ultrasound is emitted. Methods of how to select materials and modify their ultrasonic characteristics are also discussed.

Piezopolymer transducer with matching layer

Transducers to measure fluid flow using Doppler ultrasound that are suitable for integrating into or connecting to intravascular devices are disclosed. These transducers meet the requirement for long, thin, flexible transducers, and consist of one or more diffraction-grating transducers, with or without non-diffraction-grating transducers. An exemplary configuration of the transducers utilizes the diffraction caused by narrow transducers to produce beam overlap for Doppler detection of moving blood, and stripline transmission lines are used to bring energy to and receive energy from the transducers and may carry the disclosed transducer configurations as well as carry signals into and out of the blood vessels.

Transducer apparatus and method for intravascular blood flow measurement

A system for monitoring blood flow confined by at least one vessel wall, the system including: at least one implantable diffraction-grating transducer being embedded within or adjacent to a vessel wall, the diffraction-grating transducer being suitable for emitting ultrasound into or receiving Doppler shifted ultrasound from the blood flow; and, a source for pulse-exciting the implantable diffraction grating; wherein, the Doppler shift is indicative of the blood flow.

Vessel flow monitoring system and method

A dual spiral transducer and method of manufacture of same is disclosed. In one aspect, the transducer comprises a central rod, a first spiral piezoelectric electrode wrapped around a circumference of the rod, the electrode being advanced around the rod at a determined angle determined based on a length of a single complete turn around the rod and a diameter of the rod and a second spiral piezoelectric electrode wrapped around the circumference of the rod, the second spiral electrode being electrically isolated, and offset, from the first spiral electrode by a known distance. A second set of spiral electrodes can be integrated into the structure so that both transmission and reception of signals is feasible.

Transducer apparatus for intravascular blood flow measurement

An ultrasound system provides Doppler spectral data indicative of a monitored moving fluid. The spectral data is analyzed according to the level of power in specified Doppler frequency ranges. Audio signals indicative of each analyzed range are generated to enable a user to audibly determine said range is in order to detect a certain condition manifested by said fluid motion.

Ultrasonic apparatus and method for generating audio signals using doppler

An apparatus and method for detecting the highest velocity of fluid flow with in a volume having multiple sources of fluid flow with different velocities. There are multiple pairs of receiving transducers arranged about a region wherein each transducer in a pair is positioned on the same axis with respect to the region. A transmitting transducer is positioned at the region to provide an output frequency signal, which frequency signal is transmitted to the fluid flow area volume. This causes Doppler shifted frequency signals to be reflected, with the Doppler shift being a function of the fluid flow velocity. Each of the receiving transducers receive the Doppler shifted signals. Signal processing means are responsive to the Doppler shifted signals and the original transmitted output frequency signal to process those signals to provide a velocity signal for each pair of transducers. One then selects the maximum velocity signal obtained from the pair. By obtaining the maximum velocity signal, one then knows the direction of the maximum fluid flow which is determined by the axis pair of receiving transducers are located on.

Angle-independent doppler system for screening

An apparatus for determining the velocity of a fluid flowing through a lumen comprises a first diffraction grating transducer (DGT) responsive to a continuous wave (CW) input and operable in a first mode for producing a first signal beam at a first frequency and first phase, and in a second mode for producing a second signal beam at the first frequency and a second phase; a second diffraction grating transducer (DGT) operating as a receiver and coupled to the first diffraction grating transducer at a predetermined angle, the second diffraction grating transducer producing a first beam which intersects the first DGT first beam for receiving a first reflected signal associated with the first signal beam, and for producing a second beam which intersects the first DGT second beam for receiving a second reflected signal associated with the second signal beam; the first beams adapted to intersect in a first predetermined region through which dynamic particles are undergoing velocity analysis, and the second beams adapted to intersect in a second predetermined region through which dynamic particles are undergoing velocity analysis; and electronic circuitry responsive to the first and second reflected signals for comparing with the first frequency and the first and second phase to determine the velocity of the fluid.

Angle-independent continuous wave doppler device

An ultrasonic imaging apparatus comprising a transducer operative for receiving a pulse of energy containing multiple frequencies and generating a plurality of beams at different angles corresponding to a plurality of frequencies toward an object to be imaged; means for focusing said beams to produce an array of focused points at spatial positions on the object; a receiver for receiving reflected signals from the object having frequencies corresponding to the spatial positions and simultaneously filtering the reflected signals to produce sample image data sets corresponding to spatial positions at particular time intervals; and means for producing rotational motion between the transducer and the object to enable generation of sample image data sets at other predetermined spatial positions; and means for summing the sample image data sets at each of the predetermined spatial positions to produce an image of the object.

Multi-beam diffraction grating imager apparatus and method

A higher-order quadrature driven diffraction grating ultrasonic transducer and mode of operation, useful for determining the velocity of a fluid under investigation. The diffraction grating of the transducer is easier to fabricate compared to prior art first order quadrature driven diffraction grating ultrasonic transducers because the higher order design allows the grating to be expanded. The higher order design also eliminates the need to vary the frequency or phase of pulse generator used to drive the transducer in order to produce multiple beams needed for fluid velocity measurements.

Higher-order quadrature driven diffraction grating doppler transducers

An apparatus and method is disclosed for locating a desired blood vessel within a predetermined volume of tissue. The apparatus and method includes a plurality of transducers which are operable to be positioned over the tissue. Each of the transducers when driven produces an output signal indicative of a characteristic of a blood vessel located under each transducer. A control system for selectively driving the transducers in order to produce a plurality of output signals and for comparing the plurality of output signals in order to determine the output signal having the largest amplitude which corresponds to the transducer positioned over the desired blood vessel.

Apparatus and method for automatic placement of transducer

An ultrasonic transducer apparatus of variable frequency including a diffracting structure adapted for emitting and receiving a plurality of diffracted ultrasonic beams of calculable different angles for determining the velocity of a fluid flowing through a lumen, and flow volume. Velocity and flow volume are determined from at least two equations in the two unknowns of the velocity, and the angle between the ultrasonic transducer apparatus and the direction of the fluid flow, and from a determination of the diameter of the lumen.

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Princeton, NJ, United States of America

David Vilkomerson