Coil embolisation has been the standard transcatheter technique for occlusion of pathologic vessels, aneurysms, and fistulae for more than three decades. Tungsten is an attractive material for use as an endovascular coil, because of its high radiopacity and thrombogenicity.1 Recently, decreasing radiopacity has been reported in patients after implantation of tungsten coils (MDS, Balt Extrusion, Montmorency, France) into cerebral aneurysms > 30 months after implantation.2 Analysis of the coils in an experimental study demonstrated “a clear degree of iron” around the MDS coil occluded arterial aneurysms. The authors concluded: (1) that the coils are not purely tungsten; (2) that there was corrosion of the coils; and (3) that it may be dangerous to use this type of coil in patients.3 To assess whether similar findings could be observed in our patients all transcatheter tungsten coil …