Abstract: Method for providing micro-miniature high efficiency ultrasonic transducer assembly having a diameter of 0.018 inches or less. A transducer is formed from a selected transducer material to provide a cylindrical transducer having front and back sides with a thickness which is one-half of the diameter of the transducer +/-5%. The frequency constant of the material is ascertained. The frequency of operation of the transducer is ascertained by dividing the frequency constant by the thickness of the transducer in mils. The transducer is mounted in a housing and leads are secured to the front and back sides of the transducer.

Abstract: Apparatus for measuring the volumetric flow of a liquid in a vessel having a wall and having an axis extending longitudinally of the vessel parallel to the vessel wall. A flexible catheter is provided which has a longitudinal axis adapted to be disposed in the vessel. The catheter has front and back sides. First, second, third and fourth transducers are carried by the catheter. The first, second and fourth transducers are disposed on the front side of the catheter and the third transducer is positioned on the back side of the catheter. The second and fourth transducers are spaced apart a predetermined distance. The first, second and third transducers comprise a first set of transducers and the first, third and fourth transducers comprise a second set of transducers. Instrumentation is connected to the first, second, third and fourth transducers. The instrumentation causes the first, second, third and fourth transducers to emit ultrasonic energy beams therefrom.

Abstract: System for measuring a characteristic of flow of liquid in a vessel of a patient comprising a transducer positioned in a vessel in a patient for supplying ultrasonic energy. The transducer produces a substantially uniform beam which encompasses the vessel. The transducer receives ultrasonic energy back scattered from the red blood cells and provides an electrical output signal. A first moment detector is provided which receives the electrical output from the transducer and provides a first moment signal. Normalization is provided to the output of the first moment detector to provide an electrical output representing a characteristic of the flow of the liquid in the vessel.

Abstract: Apparatus for measuring volumetric flow of a liquid in a vessel having a wall and having an axis extending longitudinally of the vessel parallel to the vessel wall. A flexible catheter is adapted to be disposed in the vessel. First and second ultrasonic transducers are carried by the catheter on one side of the catheter and face the wall of the vessel so that the beams from the transducers each cross substantially the longitudinal axis of the vessel. The first transducer beam is inclined at an angle with respect to the longitudinal axis of the vessel. The second transducer beam is inclined in a direction which is generally perpendicular to the longitudinal axis of the vessel.

Abstract: Guidewire comprising a flexible elongate member having a distal extremity with an ultrasonic transducer secured to the distal extremity of the flexible elongate member. The transducer has a diameter ranging from 0.007 inches to 0.018 inches and has a thickness and a diameter to provide a transducer having an aspect ratio with a thickness which is one-half of the diameter .+-.5%. Electrical leads are connected to the transducer and extend the length of the flexible elongate member.

Abstract: System for measuring a characteristic of flow of liquid in a vessel of a patient comprising a transducer positioned in a vessel in a patient for supplying ultrasonic energy. The transducer produces a substantially uniform beam which encompasses the vessel. The transducer receives ultrasonic energy back scattered from the red blood cells and provides an electrical output signal. A first moment detector is provided which receives the electrical output from the transducer and provides a first moment signal. Normalization is provided to the output of the first moment detector to provide an electrical output representing a characteristic of the flow of the liquid in the vessel.

Abstract: A guide wire assembly comprising a guide wire with first and second conductors which extend along the length thereof. The guide wire also comprises a flexible cable having first and second conductors which extend along the length thereof. A connector assembly is provided for interconnecting the flexible cable to said guide wire and interconnecting the conductors carried thereby. The connector assembly includes a male connector with a sleeve and a conductive core which is mounted in the sleeve. An insulator is mounted in the sleeve and insulates the conductive core from the sleeve. A conductive band is carried by the insulator and is spaced from the sleeve. The first and second conductors are disposed within the sleeve. The first connector is connected to the conductive core and the second conductor is connected to the conductive band.

Abstract: A guide wire assembly comprising a flexible guide wire having a diameter of 0.018 inches or less and having a connector assembly. The connector assembly includes male and female connectors. The male connector includes a conductive coil spring and a core wire which extends beyond the conductive coil. The female connector includes a recess for receiving the core wire as well as a conductive element for engaging the coil spring.

Abstract: Apparatus for measuring volumetric flow of a liquid in a vessel having a wall and having an axis extending longitudinally of the vessel parallel to the vessel wall. A flexible catheter is adapted to be disposed in the vessel. First and second ultrasonic transducers are carried by the catheter on one side of the catheter and face the wall of the vessel so that the beams from the transducers each cross substantially the longitudinal axis of the vessel. The first transducer beam is inclined at an angle with respect to the longitudinal axis of the vessel. The second transducer beam is inclined in a direction which is generally perpendicular to the longitudinal axis of the vessel.

Abstract: Device for measuring volumetric blood flow in a vessel comprising a catheter having proximal and distal extremities. A balloon is carried by the distal extremity of the catheter. A balloon inflation lumen is carried by the catheter and is in communication with the balloon. A toroidal ultrasonic transducer is carried by the catheter and is spaced proximally of the balloon. Electrical circuitry is provided for supplying electrical energy to the transducer. The transducer produces a large substantially uniform beam of ultrasonic energy to illuminate a vessel of approximately three centimeters in diameter with the ultrasonic energy.

Abstract: Catheter for making measurements in a vessel defined by a wall carrying a fluid comprising an elongate flexible tubular member having a plurality of lumens extending therethrough and having proximal and distal extremities. An inflatable balloon is carried by the distal extremity of the tubular member and has the interior of the balloon in communication with one of the lumens in the flexible tubular member. The tubular member has at least one predetermined bend therein adjacent the distal extremity of the tubular member. A transducer is carried by the tubular member in the region of the predetermined bend. Conductors are connected to the transducer and are carried by the tubular member and extends through one of the lumens in the tubular member to the proximal extremity of the tubular member. The tubular member has an opening in the distal extremity distal of the balloon in communication with one of the lumens in the tubular member.

Abstract: A catheter having a mechanism for positioning a doppler shift transducer carried by the catheter against a side wall of a blood vessel. A portion of the catheter near the distal end is adjustable for movement between a first position in line with the axis of the catheter and a second position in which such catheter portion is in the shape of an arc extending outward from the axis of the catheter such that the arcuate portion will wedge the body of the catheter against the other wall of the blood vessel. The adjustable portion can be manipulated using a mechanism near the proximal end of the catheter outside of a patient's body.