Abstract: A system for endoscopic detection of blood flow is disclosed. A catheter is sized to pass through the biopsy channel of an endoscope and includes an elongated catheter tube of flexible material and an ultrasonic probe carried by the catheter tube adjacent its tip. Depending on the application, the ultrasonic field provided by the ultrasonic probe may be either transverse or parallel to the longitudinal axis of the catheter tube and may be either highly directional, omnidirectional, or sectorial. The ultrasonic probe is coupled to a pulsed Doppler circuit (FIG. 16) by an isolation circuit (FIG. 20) that provides electrical isolation and RFI suppression. The Doppler circuit is designed to enhance close proximity detection of blood flow, to limit the range of the probe's ultrasonic field, and to distinguish between arterial blood flow, venous blood flow, and vessel wall motion.

Abstract: Various forms of a catheter that is sized to pass through the biopsy channel of an endoscope include an elongated catheter tube of flexible material and an ultrasonic probe carried by the catheter tube adjacent its tip. The forms include: a papillotome catheter (FIGS. 1 and 3); catheters for general endoscopic and nonendoscopic applications (FIGS. 4, 7A through 7C, 8A through 8B, 10A through 10B, and 11); and, a sclerosing catheter (FIGS. 13 through 15). These catheters may be used to determine the location of the retroduodenal artery in endoscopic papillotomy (FIGS. 2, 5, and 6), to evaluate and treat esophageal varices (FIGS. 9 and 12), or generally to detect blood flow in a biological structure within the body. Depending on the application, the ultrasonic field provided by the ultrasonic probe may be either transverse or parallel to the longitudinal axis of the catheter tube and may be either highly directional, omnidirectional, or sectorial.

Abstract: A system for detecting and quantifying air emboli in blood vessels which uses either an intravascular catheter 22 or an esophageal catheter 50. In a preferred embodiment, the intravascular catheter includes an elongated cylindrical tube of flexible material, the tube having a tip 22A and having formed therein an axial aspiration lumen 26 and a second axial lumen 28. An ultrasonic transducer 24, comprising an annular, cylindrical ring of piezoelectric material, is fitted over and secured to the tube adjacent its tip. A microcaxial cable passes through lumen 28 and is electrically interconnected with the ultrasonic transducer. In a preferred embodiment, the esophageal catheter includes a substantially cylindrical member 54 on which is fitted an ultrasonic transducer 52 comprising an annular, cylindrical ring of piezoelectric material.

Abstract: A system for detecting and quantifying air emboli in blood vessels which uses either an intravascular catheter 22 or an esophageal catheter 50. In a preferred embodiment, the intravascular catheter includes an elongated cylindrical tube of flexible material, the tube having a tip 22A and having formed therein an axial aspiration lumen 26 and a second axial lumen 28. An ultrasonic transducer 24, comprising an annular, cylindrical ring of piezoelectric material, is fitted over and secured to the tube adjacent its tip. A microcoaxial cable passes through lumen 28 and is electrically interconnected with the ultrasonic transducer. In a preferred embodiment, the esophageal catheter includes a substantially cylindrical member 54 on which is fitted an ultrasonic transducer 52 comprising an annular, cylindrical ring of piezoelectric material.