Abstract: Front-end and side-on intravascular catheters are described that comprise an abrasive head contained substantially within a housing. Aspiration means and flushing means are connected to the region of grinding to remove dislodged debris. A preferred embodiment has the abrasive surface of a rotatable head comprised of diamond powder. Another preferred embodiment has an ultrasonic transducer affixed to the head to permit transluminal imaging of the site of occlusion.

Abstract: An improved electrical interconnection system for an ultrasonic transducer included in an intraluminal catheter is electrically isolated from the imaging core and provides for a balanced transmission line to improve noise rejection.

Abstract: A flexible drive cable comprises a flexible cable body, a pair of electrically insulated wires disposed through an axial lumen of the cable body, and a resilient support tube disposed over the wire pair. The resilient support tube provides support for the wire pair to help the wire pair recover from bending and deformation which may occur during storage or use of the drive cable. The support tube is usually liquid impermeable to maintain an air gap around the wire pair. The air gap improves shielding and maintains a constant overall impedance across the drive cable. The drive cable may be combined with an ultrasonic transducer at its distal end to form an ultrasonic transmission core.

Abstract: A longitudinal position translator includes a probe drive module and a linear translation module. The probe drive module is coupled operatively to an ultrasonic imaging probe assembly having a distally located ultrasound transducer subassembly in such a manner that longitudinal shifting of the transducer subassembly may be effected. The probe drive module is preferably mounted to the linear translation unit so as to be moveable between a condition whereby longitudinal shifting of the transducer subassembly can be conducted either manually or automatically. When in the automatically-operable condition, the probe drive module will be engaged with a motor-driven screw associated with the linear translation module so as to cause the probe drive module to be longitudinally displaced at a constant motor-driven rate. In this manner, the distally located ultrasound transducer is longitudinally shifted during an ultrasound scan of surrounding intravascular (or other) tissue to thereby allow axially-spaced 360.degree.

Abstract: The present invention provides improvement usable with an intravascular catheter having a single common distal lumen with a reduced profile connected to two or more proximal lumens. The catheter will be loadable over a guidewire into a region of interest within a patient's vascular system. According to one aspect of the present invention, means are provided to ensure that the guidewire enters into a desired one of the proximal lumens. In a preferred embodiment, a special tool is provided to achieve this. According to a second aspect of the present invention, the catheter is provided with a proximal housing and an axially expandable member to shield the rotating parts at the proximal end of the catheter and to allow for convenient movement of a work element within the catheter body.

Abstract: The claimed invention provides an improved tracking tip for use with a work element in a catheter system having a flexible tubular catheter body. Use of a tracking tip according to the present invention will facilitate advancement of the work element within the catheter body and will substantially eliminate the possibility that the work element will puncture the catheter body. Preferred embodiments will comprise a wire coil and will often include a rounded end member, which may be in the form of a solder ball, at the distal tip of the wire coil. In some embodiments, the rounded end member may be coated with a lubricant or a suitable non-stick material to further improve tracking of the work element within the catheter body.

Abstract: The present invention provides an improved imaging catheter which is pre-filled with a fluid suitable for the transmission of imaging signals. Such a catheter eliminates the need for the user to fill and flush the catheter with fluid prior to its use. A catheter according to the present invention may be stored in a container which itself contains fluid to prevent fluid loss. Some embodiments will include reservoirs to hold a supply of fluid to replace that lost, for example, to evaporation. In some embodiments, these reservoirs will further include means for applying pressure to the fluid contained therein so that new fluid is forced into the catheter to replace any fluid lost.

Abstract: Front-end and side-on intravascular catheters are described that comprise an abrasive head contained substantially within a housing. Aspiration means and flushing means are connected to the region of grinding to remove dislodged debris. A preferred embodiment has the abrasive surface of a rotatable head comprised of diamond powder. Another preferred embodiment has an ultrasonic transducer affixed to the head to permit transluminal imaging of the site of occlusion.

Abstract: A catheter for ultrasonic imaging has a transducer fixed to a cutter. The transducer is moved longitudinally within an artery while in a fixed radial position. Ultrasonic reflections are received and processed to display a planer or rectangular field of view image area of the artery. Other axial planes of the artery can be imaged by radially turning the transducer to a different angular orientation within the artery and then longitudinally moving the transducer to obtain an image of another planer field of view.

Abstract: An intraluminal imaging catheter system for viewing segments of vessels downstream of the catheter itself is provided. The catheter system incorporates an ultrasonic transducer pivotally mounted adjacent the catheter's distal end. A flexible drive means disposed within a flexible tubular member adapted for insertion into the vessel causes the transducer to pivot back and forth to scan a segment of the vessel. Optionally, the forward viewing catheter system of the present invention may be combined with a work element such as a biopsy tool or other device for use in conjunction with the imaging capability.

Abstract: In an ultrasound imaging system, ultrasound echoes representing vessel walls are distinguished from ultrasound echoes from blood by using a classifier which employs the mean and variance of the raw data of gray intensities as acquired directly from an ultrasound scanner detector. In a specific embodiment, the statistical parameters of mean and variance are determined in the course of real-time processing and prior to attempted classification and then are used as parameters representing the true image as acquired.

Abstract: In an intraluminal ultrasound imaging system, ultrasound echoes representing vessel walls are distinguished from ultrasound echoes from blood by detecting and examining the phase of all received ultrasound echoes, extracting selected parameters from the phase information and utilizing the extracted parameters to suppress ultrasound echoes representing blood, thereby to enhance the lumen-to-vessel wall contrast. In a first embodiment, parameters are derived from a phase difference between echoes in approximately the same spatial location, including comparisons between neighboring image vectors of the same image frame or comparison between vectors on successive image frames. Selected parameters may be extracted based on statistics of the phase signal or the phase difference signal or from the slope of the phase difference or the phase signal, either between neighboring image vectors in the same image frame or between images of successive image frames.

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: A longitudinal position translator includes a probe drive module and a linear translation module. The probe drive module is coupled operatively to an ultrasonic imaging probe assembly having a distally located ultrasound transducer subassembly in such a manner that longitudinal shifting of the transducer subassembly may be effected. The probe drive module is preferably mounted to the linear translation unit so as to be moveable between a condition whereby longitudinal shifting of the transducer subassembly can be conducted either manually or automatically. When in the automatically-operable condition, the probe drive module will be engaged with a motor-driven screw associated with the linear translation module so as to cause the probe drive module to be longitudinally displaced at a constant motor-driven rate. In this manner, the distally located ultrasound transducer is longitudinally shifted during an ultrasound scan of surrounding intravascular (or other) tissue to thereby allow axially-spaced 360.degree.

Abstract: The present invention provides an improved drive shaft for use in a catheter system having a rotating imaging or interventional work element. A drive shaft according to the present invention is formed at least in part of a material having super elastic properties. This material provides an advantageous combination of column strength and torsional rigidity with the ability to sustain substantial bending without permanent deformation. Preferred embodiments are formed as hollow tubes to allow electrical conducting wires to be disposed within the body of the drive shaft. Some embodiments combine relatively rigid proximal segments with relatively flexible distal segments to allow for entry of the work element into narrow and twisting regions of a patient's vascular system.

Abstract: The present invention provides improvement usable with an intravascular catheter having a single common distal lumen with a reduced profile connected to two or more proximal lumens. The catheter will be loadable over a guidewire into a region of interest within a patient's vascular system. According to one aspect of the present invention, means are provided to ensure that the guidewire enters into a desired one of the proximal lumens. In a preferred embodiment, a special tool is provided to achieve this. According to a second aspect of the present invention, the catheter is provided with a proximal housing and an axially expandable member to shield the rotating parts at the proximal end of the catheter and to allow for convenient movement of a work element within the catheter body.

Abstract: An improved ultrasonic imaging catheter assembly (4) includes an elongate tubular assembly (8) having an imaging assembly (12) at one end (14) and one or more connectors (16) at the other end (17). The catheter assembly includes a digital identification circuit (26), used to permit the automatic identification of the catheter assembly, having a common ID terminal (32) and at least first (34) and second (36) signal terminals. The common ID terminal is connected to each of the first and second signal terminals in one of four different ways: a short circuit, an open circuit, by a diode (80a) with the cathode of the diode towards the common ID terminal, and by a diode (80b) with the cathode of the diode towards the signal terminal.

Abstract: An ultrasonic imaging catheter comprises a catheter body having a distal region and proximal region. The distal region has a reduced cross-sectional area compared to that of the proximal region, and the proximal region includes at least two lumens therethrough for accommodating a movable guidewire and a rotatable working element, respectively. The catheter body may be inserted over the moveable guidewire, with the guidewire passing through a lumen in the distal region and the guidewire lumen in the proximal region. After positioning the catheter body, the guidewire can be retracted from the distal region and into the proximal region, leaving the lumen in the distal region available for the rotatable working element. Such a construction allows over-the-wire imaging of the catheter while minimizing the width of the catheter in the distal region which remains available for placement of the working element.

Abstract: An ultrasonic imaging catheter comprises a flexible catheter body having a rigid housing at its distal end. A tapered flexible end piece is secured to the distal end of the rigid housing, and a flexible guide wire tube extends in parallel to both the housing and the flexible end piece from the catheter body. The guide wire tube defines a guide wire lumen capable of receiving a movable guide wire, and the combined structure of the housing, flexible end piece, and flexible guide wire tube minimize constriction of the guide wire as it passes through the guide wire lumen.

Abstract: A combined ultrasonic imaging and dilatation catheter includes an inflatable dilatation balloon located at the distal end of a flexible catheter body. An ultrasonic imaging system including a fixed ultrasonic transducer and a rotatable reflective surface capable of deflecting an ultrasonic signal from the transducer is located adjacent to, but axially spaced-apart from the dilatation balloon. The dilatation balloon in the interior of the imaging housing are isolated, and separate lumens are provided for inflating the balloon and flushing the imaging housing. In this way, the balloon may be inflated with a contrast medium suitable for fluoroscopic imaging, while the imaging housing may be filled with a different medium suitable for ultrasonic imaging.