Importance

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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. The ultrasonic probe is coupled to a pulsed Doppler circuit (FIG. 16) by an isolation circuit (FIGS. 17 through 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.

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First Claim