A combined radiopaque indicator and lumen plug for a multi-lumen catheter is made of a flexible, coiled metal spring having balled ends formed by resistance welding the ends of the coiled spring. The coiled spring plug is affixed within one or more lumens of a catheter to provide a radiopaque indica...http://www.google.se/patents/US4577637?utm_source=gb-gplus-sharePatent US4577637 - Flexible metal radiopaque indicator and plugs for catheters
