Onyx is a stable embolic material, although recurrence of seemingly completely occluded DAVFs may develop because of postembolization hemodynamic changes that accentuate primarily graphically absent residual fistula. These residuals can be diagnosed with MRA at follow-up.
The authors' data suggest that MRA could be sufficient as the follow-up diagnostic method after complete DAVF occlusion with Onyx. However, larger prospective studies on this topic are needed.