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: 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: An apparatus and method are described for imaging blood flow from within a vasculature. An ultrasound catheter probe carrying an ultrasound transducer array is inserted within a blood vessel. The transducer array emits ultrasound excitation signals and receives ultrasound echo waveforms reflected from blood and tissue in a region of the vasculature. A series of the echo waveforms resulting from a series of excitation signals are combined in a manner such that the echo signals from static features in the region, such as tissue and plaque, are significantly attenuated. The combined signal primarily represents the relatively dynamic features in the region (i.e. the blood flow). A blood flow image is constructed from the combined signal. The blood flow image is colorized and combined with an image of the relatively static features in the region. Thereafter, the combined image is displayed on a video display.

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: An apparatus and method for imaging a small cavity is disclosed wherein reference waveforms to be used in obtaining an improved image are generated in vivo instead of in vitro as is the conventional procedure. The reference waveforms are used to strip the imaging signals of noise that otherwise produces artifacts in an image generated from the signals. The imaging probe is first inserted into a first area of the vascular system to be imaged and reference waveforms are collected. After collecting the reference waveforms, the imaging probe is further inserted into the vascular system to a second area that is to be imaged. If new reference waveforms are required, the imaging probe is simply withdrawn to the first area of the vascular system wherein new reference waveforms are collected, and then the imaging probe is again further inserted to the second area, which then is imaged.

Abstract: A dilating and imaging apparatus for attaching to and receiving pressurized fluid from a distal end of a catheter. The apparatus includes an inflatable balloon and an imaging device positioned behind an expandable portion of the balloon and upstream of the flow of pressurized fluid into the balloon so as to enable the balloon to deflate and achieve a smaller diameter than that of the imaging device, thus enabling the apparatus to enter a stenosis having a smaller diameter than the imaging device. In one embodiment of the invention, the imaging device can be maneuvered within the balloon while the balloon is inflated and dilating the stenosis.

Abstract: A self-venting balloon dilatation catheter and method for producing the same having a catheter tubing including a first lumen and a second lumen. An expandable balloon is positioned at a distal end of the catheter tubing. The first lumen is for a guide wire and the second lumen is in communication with the interior of the balloon. The balloon is expanded by filling the balloon with pressurized fluid via the second lumen. An air vent within the catheter tubing purges air from the balloon when the balloon is filled with fluid. Air purged via the air vent first moves substantially transverse to a longitudinal axis of the catheter tubing and then along the longitudinal axis to an opening at a distal end of the catheter tubing. A cylindrically marker band is secured around the distal end of the catheter tuving, and another cylindrical marker band is secured around the catheter tubing inside the expandable balloon.

Abstract: An in vivo imaging device is provided for producing real-time images of small, moving or stationary cavities and surrounding tissue structure. The imaging device includes a probe assembly of very small dimensions and preferably sufficiently small to fit within cavities having a diameter on the order of that of a human coronary artery. The probe assembly may be mounted to a positioning device such as a catheter, which allows for the use of, for example, conventional guiding catheters and guide wires.