The application of Onyx (CovidienInc., Plymouth, MN, USA) has formerly been limited to neuro-interventions (1-4), but lately, embolization with Onyx has become more frequent in terms of peripheral interventions (5).Onyx is now used for treatment of endoleaks typ 1 and 2 after aortic stent-grafting (6-8), aortic pseudoaneurysms (9-10) and for abdominal bleeding control (11).The main problem in this context is the high tantalum content of Onyx, which is needed tor visualization during embolization procedure. But tantalum also causes strong CT beam hardening artifacts that restrict...

During our first experiments we distinguished the relevant range of the tantalum dosage.We manually prepared Onyx suspensions with reduced tantalum concentrations by centrifugation and re-suspension.Our first aortic phantom (Figure 3) was made from a cardboard tube that represented the aorta.We placed an aortic stent graft inside the tube that demonstrated the true, correctly perfused aortic lumen.The area around the stent graft represented the aneurysm.The stent graft and the tube were filled with mixtures of alginate and contrast media or glucose to simulate blood and thrombus....

In our first phantom, the artifact intensity decreased with decreasing amount of tantalum.According to that, visibility of endoleak reperfusion increased with decreasing tantalum content. The Onyx suspensions with 10-50% tantalum content of the original product caused a reasonable amount of artifacts that enabled diagnosis of the simulated endoleak re-perfusion. In the second phantom, for which we used the commercially mixed Onyx suspensions, we saw that simulation of severe endoleak re-perfusion could be diagnosed at tantalum concentrations less than 50% of the original product.The artifact intensity...

Finally we can conclude that Onyx suspensions with less than 50% tantalum of the original product provide the best combination of low artifact intensity and good visibility of severe endoleak re-perfusion. Corresponding to that, Onyx suspensions with less than 45% tantalum of the original product provide the same characteristics for slight endoleak re-perfusion. Simulation of fluoroscopically controlled endoleak embolization showed thatOnyx suspensions with 30% tantalum or less are baldy visible. Dueto injection of reasonable amouts before first visualzation of the cast, they bear a high...

1. Endovascular treatment of very small ruptured intracranial aneurysms: complications, occlusion rates and prediction of outcome. Starke RM, Chalouhi N, Ali MS, Penn DL, Tjoumakaris SI, Jabbour PM, Gonzalez LF, Rosenwasser RH, Dumont AS. J Neurointerv Surg. 2012 Nov 17. [Epub ahead of print]. 2. Current update on the endovascular management of intracranial aneurysms. Gupta V, Gandhi CD, Prestigiacomo CJ. J Neurosurg Sci. 2012 Sep;56(3):163-74. 3. Curative embolization of brain arteriovenous malformations with onyx: patient selection, embolization technique, and results. van Rooij WJ, Jacobs S,...