Keywords:
Interventional vascular, Arteries / Aorta, Vascular, CT-Angiography, Fluoroscopy, Catheter arteriography, Embolisation, Experimental investigations, Arthrography, Aneurysms, Artifacts, Prostheses
Authors:
K. M. Eberhardt, D. Maxien, M. F. Reiser, M. Treitl; Munich/DE
DOI:
10.1594/ecr2013/C-0276
Methods and Materials
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.
The manually prepared Onyx suspensions were then filled into the endoleak cavities after removal of the wood sticks and surrounded by a mixture of alginate and glucose to simulate re-perfusion of the endoleak (Figure 4). We evaluated the artifact intensity of the manual Onyx suspensions and the visibility of the endoleak re-perfusion in a CT scan.
After the initial examinations,
we received the relevant,
commercially prepared Onyx suspensions from the vendor and injected them fluoroscopically controlled into our second aortic phantom.
This second phantom also simulated a stented aortic aneurysm and further contained a flow model with several endoleak cavities. It contained the same compartments like the first one,
but it had only 7 endoleak cells,
which were all connected to a small tube for perfusion.
This way we could simulate trans-catheter injection of the new Onyx suspensions.
The endoleak cells were further surrounded by a second tube system that had a triangular form and represented different amounts of endoleak re-perfusion. The upper part of these triangular cavities extended to 5mm in order to represent severe endoleak re-perfusion. The cavities` axial diameter decreased to 1mm in order to demonstrate also smaller and slight endoleak re-perfusion.
The second aortic phantom was a plastic tube system that was designed by computer and printed by a 3D printer. Instead of alginate we used gelatin as filing material,
which again was mixed with glucose or contrast media in order to simulate the correct CT-densities of blood,
thrombus and endoleak. We evaluated the visibility of the commercially prepared Onyx suspensions during the embolization process as well as the amount of Onyx that was injected until we recognized the first drop at the end of the catheter.
We further evaluated the artifact intensity,
the diagnostic image quality and the visibility of the cavities simulating endoleak re-perfusion.