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✓ An improved magnetically-guided intravascular catheter system in dogs is described as safe, requiring little attention, allowing the application of flow surges to aid propulsion of the tip, and providing for angiography of good quality. Current concepts of the relationship of magnetic and flow guidance are discussed. The uses of the system demonstrated include selective angiography, perfusion of isobutyl-2-cyanoacrylate into experimental arteriovenous fistulas, and perfusion of microparticulate iron suspensions into experimental aneurysms. A unique detachable macroballoon that may function as a reversible tethered embolus is reported.

A magnet system capable of guiding a ferromagnetic-tipped catheter through vessels in the body would greatly facilitate many medical treatments by providing access to parts of the body otherwise inaccessible except by major surgery. A rotatable iron magnet which has been employed in preliminary experiments with laboratory animals has indicated the feasibility of this technique, but a more advanced system is required for sophisticated medical applications. This paper describes a proposed design for a superconducting magnet system, with a 10 in. room-temperature access, which can exert an arbitrarily directed force of 200 times that of gravity on a tip anywhere within the head. A larger but otherwise similar system could be used for cathetarization of any part of the body.