| 摘要 |
A thin walled needle having a body section containing a sharp tipped obturator for insertion into a fetal vessel or cavity through the mothers abdominal wall using ultrasonic imaging to guide and position the needle. After being located within a desired position within the vessel, the obturator is withdrawn from the body section and a balloon that is mounted upon the end of a catheter is past through the body section into a treatment region where the balloon is inflated. A sleeve is shrink fitted upon the needle body so that the air is trapped between the sleeve and the needle body which provide a bright ultrasonic echo. The distal end of the sleeve protrudes outwardly beyond the tip opening of the needle body so that when the catheter is withdrawn back into the needle body with the balloon in a deflated state, the balloon will slide easily into the sleeve protrusion and will be shaped by the sleeve so that it will move freely into the distal opening in the needle body without the danger of the balloon becoming snagged or hung up on the needle body. |
