Abstract: An exceptionally flexible, ultrasoft vaso-occlusive or embolism forming device made of a material which may be a braid, coil, or chain which forms a long, thin thread-like device having little rigidity or column strength. The device is sufficiently flexible and small that it may be hydraulically delivered to a site within the vasculature of a human body using an injected drug or fluid flush through a catheter.

Abstract: An infusion catheter with an elongate tubular body having proximal and distal ends and a lumen extending between the ends through which a diagnostic, therapeutic, or vasoocclusive agent can be delivered is disclosed. The elongate tubular body is formed of a relatively stiff tapered proximal segment, a relatively flexible and strong distal segment, and a transition section that is less flexible than the distal segment but more flexible than the proximal segment. The infusion catheter is directed to the target site by means of the flow of blood to that site.