Abstract: An ultrasound transducer array (408) includes at least one transducer element (412) having a first (604) and second (606) portions separated by an acoustical discontinuity (520). The first portion (604) has the desired length to form a half-wave k31 resonance, while the second portion (606) has a resonant length for an undesired very low frequency out-of-band k31 resonance. The thickness of the transducer element (412) is designed for k33 half-resonance. Given the design, the transducer element (412) can operate and provide for both forward-looking (514) and side looking (512) elevation apertures. A method is also disclosed for using the disclosed ultrasound transducer (412) in ultrasound imaging.

Abstract: A device and method for precisely delivering dosage of radiation from a radiation source to a treatment site of a vessel is provided herein. In one embodiment, the device includes a catheter which inserts into a vessel lumen of the body. The catheter includes an adjuster section for altering a portion of the radiation emitting radially from the radiation source so that the radiation source delivers an asymmetrical radiation profile to the vessel. The device can also include a catheter supporter which inhibits rotational deformation in the catheter between a catheter distal end and a catheter proximal end. This allows the delivery section to be precisely rotated to properly position the adjuster section within the vessel lumen.

Abstract: A swivel tip assembly (100) includes a housing (110) having a passageway (128) with proximal (112) and distal (114) openings. Spherical member (106) and bushing (108), which is captured by the housing (110), provide a swivel joint. A wire (102), which is coupled to the spherical member (106), is attached to the distal end of a catheter (50). The swivel joint allows the housing (110) to swivel or rotate freely thereby minimizing the opportunity of grabbing the guide wire (116) as the catheter (504) is being pushed or pulled along the guide wire (116).

Abstract: A device is disclosed for withdrawing a catheter or a probe from a body cavity or a body vessel with a drive which preferably is a friction drive and engages the axially movable part of the catheter. The drive is formed by at least one roller which is mounted for rotation around a shaft extending transversely to the direction of pull, which roller cooperates with at least one spring-loaded counter-roller, the rollers enclosing the catheter or the probe, with at least one roller being connected to a driving motor.

Abstract: An ultrasound catheter is disclosed for providing substantially real-time images of small cavities. The ultrasound catheter is characterized by separate and distinct materials for backing the transducers and for carrying the electronics components. The separate materials comprise an electronics carrier meeting the requirements for holding the integrated circuit of the ultrasound device and a backing material displaying superior characteristics relating to reducing ringing and minimizing the effect of other sources of signal degradation in the transducer assembly. Also, in accordance with the present invention, a technique is described for connecting the conductor lines of the separate transducer assembly and electronics body.

Abstract: An electrical device such as a pressure guide wire (700) which has a resistive pressure sensor, such as a piezoresistive sensor (208), uses a precision interconnect in order to provide proper pressure measurement readings. The precision interconnect helps avoid the effects of contact and line resistance on the measurement of the pressure sensor's resistors (402 and 404). The precision interconnect uses high input impedance device's such as differential operational amplifiers (902, 904) in order to overcome the effect of any changes in the contact resistance. Further, an interface switch (1110) which is responsive to a control signal (1106) automatically determines what type of pressure guide wire (10 or 700) is attached to the interface circuit (1200).

Abstract: A catheter position guide (100) includes a first open channel (104) along the length of the position guide (100) designed to receive a catheter (202). An optional second channel (112) substantially on the opposite side of the first channel (104) is designed to receive a guide wire (204). One or more hubs (106, 108) help retain the catheter position guide's proximal end (110) to a pullback device (310).

Abstract: A method to measure spatial fluid flow components and their velocity profiles in a number of locations in a cross-sectional area of a lumen or other body cavity by using ultrasound in which the cross-sectional area is interrogated by a plurality of ultrasonic beams; the estimation of the spatial flow components is obtained from a combination of estimations of axial, lateral and total flow; the estimation of one or more flow components is obtained through any combination of time-shift and decorrelation analysis of two or more beam-signals of the interrogating ultrasound transducer, and the estimation accuracy is further improved by the use of a reference decorrelation curve.

Abstract: A flexible elongate member such as a pressure guide wire (1000) includes an electrical device such as a pressure sensor (1002). The pressure sensor (1002) is electrically connected to conductive bands (304), (306) and (308) located on electrical connector (300). The electrical connector is attached to core wire (602) and shaft or hypotube (704). The use of electrical connector (300) helps minimize the assembly time of pressure guide wire (1000), as well as minimize some of the assembly problems associated with prior art designs such as pressure guide wire (100).

Abstract: Method and apparatus for making an image of a lumen and surrounding tissue in a body by inserting a transducer in the cavity and emitting ultrasound signals and collecting and processing echo signals to form an image, where the apparatus includes a signal processor arranged for performing the steps of and the method includes the steps of:a) obtaining echo signals from tissue at a given state of mechanical stress in a chosen direction;b) obtaining similar echo signals after a change of the mechanical stress;c) identifying the lumen-tissue boundary;d) comparing the echo signals to obtain a parameter indicative of tissue stiffness;e) performing similar steps for a number of directions;f) deriving and displaying the conventional echo image of the lumen and surrounding tissue from the echo signals of step a);g) superimposing in said image the tissue stiffness as a coded line along the lumen-tissue boundary.

Abstract: An ultrasound catheter is disclosed for providing substantially real-time images of small cavities. The ultrasound catheter is characterized by separate and distinct materials for backing the transducers and for carrying the electronics components. The separate materials comprise an electronics carrier meeting the requirements for holding the integrated circuitry of the ultrasound device and a backing material displaying superior characteristics relating to reducing ringing and minimizing the effect of other sources of signal degradation in the transducer assembly. Also, in accordance with the present invention, a technique is described for connecting the conductor lines of the separate transducer assembly and electronics body.

Abstract: A guide wire having pressure sensing capabilities for measuring the pressure of liquid in a vessel comprising a flexible elongate member and having proximal and distal extremities and having an outside diameter of 0.018" or less. The distal extremity of said flexible elongate member is adapted to be disposed in the liquid in said vessel. A housing is carried by the flexible elongate member and has a diameter substantially the same as the diameter of the flexible elongate member. The housing has a space therein with a pressure sensor mounted in the space in the housing. The pressure sensor has a diaphragm that is sensitive to changes of pressure in the liquid in the vessel. The diaphragm is rectangular in shape and is bordered by a rim surrounding the well. A backing plate is formed of an insulating material bonded to the crystal and serves to reinforce the rim of the crystal of semiconductor material.

Abstract: Catheter assembly in which an imaging transducer is positioned proximally of a treatment device at the distal end of a catheter. Unrestricted flow between a fluid lumen in the catheter and the treatment device is provided by an annular passageway formed between the walls of a marker tube which extends through the transducer and a guide wire tube which passes through the marker tube, and by a plenum chamber which is formed between the distal end of the catheter and the proximal end of the marker tube in communication with the fluid lumen and the flow passageway. The catheter, the treatment device, and the transducer are all constructed as individual modular units which can be assembled together as desired to form the assembly.

Abstract: An ultrasound transducer assembly of the present invention includes a flexible circuit to which an ultrasound transducer array and integrated circuitry are attached during fabrication of the ultrasound transducer assembly. Integrated circuitry and transducer elements are attached to the flexible circuit while the flexible circuit is in a substantially flat shape. The contacts of the transducer elements are positioned on substantially the same plane such that electrical contact with signal and ground lines on the flexible circuit is established without the need for conductive bridges to physically remote electrodes. In an embodiment of the invention wherein the transducer elements are arranged in a cylindrical array, gaps are entirely filled with backing material having a relatively low acoustic impedance. Structure integrity is enhanced and a path to ground facilitated by electrically conductive disks attached to the ends of the transducer assembly.

Abstract: A procedure for the determination of the true average peak velocity of particulate laden liquids in a tube, by the use of a Doppler ultrasonic transducer inserted in said tube. The average peak velocity (APV) and the null and first moment (M0 or M1) of the entire spectrum are obtained. The measured correlation between the null or first moment (M0 or M1) and APV are compared with a corresponding standard value which represents the correlation between M0 or M1 and APV upon optimal positioning of the Doppler ultrasonic transducer whereby where there is a deviation from the standard value, the transducer is moved until the values coincide.

Abstract: Ultrasonic imaging method and apparatus in which a reference waveform which is substantially free of echoes is modified to be equal to a weighted sum of the reference waveform and filtered signals from the transducing elements which transmit the ultrasonic waves and receive the reflected echoes. The modified waveform is then subtracted from the transducer signals to remove ringdown signals and provide a displayed image which is substantially free of ringdown artifacts.

Abstract: A radiation source for delivering a dose of radiation to a treatment site of a vessel is provided herein. The radiation source includes a delivery wire and a radioactive segment. The radioactive segment includes a substantially coiled or entwined radioactive wire which allows the radioactive segment to have a relatively large surface area to volume ratio. The delivery wire is made of material having a relatively short half-life, such as titanium, while the radioactive segment is made of a material, such as a rhenium or yttrium, which has a much longer half-life.

Abstract: An ultrasound catheter is disclosed for providing substantially real-time images of small cavities. The ultrasound catheter is characterized by separate and distinct materials for backing the transducers and for carrying the electronics components. The separate materials comprise an electronics carrier meeting the requirements for holding the integrated circuitry of the ultrasound device and a backing material displaying superior characteristics relating to reducing ringing and minimizing the effect of other sources of signal degradation in the transducer assembly. Also, in accordance with the present invention, a technique is described for connecting the conductor lines of the separate transducer assembly and electronics body.

Abstract: A blood flow detection and imaging method and system is described for displaying images in accordance with signals transmitted from an intravascular ultrasound transducer probe. The image processor includes means for independently designating persistence factors for smoothing calculated speed and power of the dynamic portion of a field of view within a vasculature. Furthermore, the designation of a particular image point within a field of view as a dynamic image point (such as a blood flow region) as opposed to a static image point (such as a tissue region) is determined by averaging signal values for image points proximate to an image point of interest over both time and space.

Abstract: Catheter assembly and method in which an imaging transducer is positioned proximally of a treatment device at the distal end of a catheter. Unrestricted flow between a fluid lumen in the catheter and the treatment device is provided by an annular passageway formed between the walls of a marker tube which extends through the transducer and a guide wire tube which passes through the marker tube, and by a plenum chamber which is formed between the distal end of the catheter and the proximal end of the marker tube in communication with the fluid lumen and the flow passageway. The catheter, the treatment device, and the transducer are all constructed as individual modular units which can be assembled together as desired to form the assembly.