Revista nr. 53-54 - Pompiliu Manea

(a)(b)Fig. 5 X-Ray/Fluoroscopic result showing the presence of tungsten particles in the structure ofthe occluder (a), reconstructed 3D surfaces of the Medrtonic-Hall valve after simultaneous scanof all its parts (b), reconstructed 3D surface of the occluder after independent scannUnder these circumstances, the immediate solution was to take the valve apart, thusallowing us to scan the two pieces independently. Figure 5 c shows the CAD image of theMedtronic-Hall’s occluder after independent scan.In the case of the Bjork-Shiley valve, the situation looked even worse. According to ourradiological results, the carbon-coated disk contains a highly concentrated, ring-shapedtungsten structure (Fig. 7) which is expected to change the mass distribution of the occluder andits moment of inertia also. However, scanning the both parts of the valve simultaneously wasalmost impossible, requiring its pulling apart and a separate scanning of each part.(c)Fig. 7 X-Ray image of the Bjork-Shiley valve, revealing the presence of a discontinuous ringshapedtungsten structure inside the occluder20