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.