A body compatible stent is formed of multiple filaments arranged in two sets of oppositely directed helical windings interwoven with one another in a braided configuration. Each of the filaments is a composite including a central core and a case surrounding the core. In the more preferred version, the core is formed of a radiopaque and relatively ductile material having a linear attenuation coefficient of at least 25 cm.sup.-1 at 100 KeV, e.g. tantalum or platinum. The outer case is formed of a relatively resilient material, e.g. a cobalt/chromium based alloy. Favorable mechanical characteristics of the stent are determined by the case, while the core enables in vivo imaging of the stent. Alternative composite filaments employ an intermediate barrier layer between the case and core formed for example of tantalum, niobium or platinum. To improve compatibility, a biocompatible cover layer can surround the case. The cover layer incorporates at least one of the following: tantalum, platinum, iridium, stainless steel, niobium and titanium. Yet another alternative composite filament features a radiopaque case surrounding a structural core.