TRANSPORT CATHETER AND ULTRASOUND PROBE FOR USE WITH SAME

摘要

A catheter (10) with several independent lumens (36, 40, 44, 48) for accepting probes (82) and for introducing fluid into a body cavity is disclosed. The first lumen (36) is circular in cross-section, and has a cross-sectional dimension of approximately half the maximum outer dimension of the catheter body (12). The second lumen (40) is crescent-shaped in cross-section and occupies at least a quarter of an arc around the cross-section of the catheter body (12). The large cross-section of the second lumen (40) allows for a high fluid flow rate through the lumen (40). The third lumen (44) allows for inflation of an inflation balloon (when present), and the fourth lumen (48) allows for the passing of a portion of an instrument along the length of the lumen. A probe (82) is also disclosed. The probe transducer portion (92) is constructed of a crystal hollow cylinder (94) with an inside lead (96) attached to the inner surface (106) of the crystal cylinder (94). One end (116) of the outside lead (98) is positioned close to the outer surface (108), in a plane (120) tangential to the outer surface (108), an is coupled to the outer surface (108) of the crystal cylinder (94) by a thin sputtered layer (104) of conductive material. The probe transducer (92) also includes a layer (100) of acoustically absorbing material on the proximal end (124) of the crystal (94), and layer (102) of acoustically coupling material on the distal end (126) of the crystal cylinder (94). The transducer element simultaneously generates an axially oriented signal beam (144) at one frequency and a radially oriented signal beam (146) at a different frequency. The signal beams (144, 146) are analyzed to calculate the blood flow area (A) and the blood flow velocity (V), the product of which is the blood flow rate (Q).