Comparison of high-resolution X-ray and micro-CT for experimental evaluation of intracranial stent prototypes: quality evaluation beyond CE mark.

INTRODUCTION: As digital mammography and micro-computed tomography (CT) have been used for evaluation of stents deployed in experimental animal models, we compared the two methods regarding their sensitivity to detect abnormalities in three prototypes of intracranial stents. METHODS: Three different prototypes of intracranial stents (n = 84) were implanted in various animal models. Explanted stents were examined using digital mammography and micro-CT. The images were compared with respect to maintenance of material and form and the stents were compared to one another. Histological analysis was performed as well. RESULTS: In the open-cell stents, expansion of the stent cells was detected in the majority of cases (57.1 %) using micro-CT and less frequently using mammography (42.3 %). The closed-cell stent revealed kink stenoses in mammography as well as in micro-CT (3/7, 42.9 %). Detailed reconstructions of micro-CT images showed high-grade kink stenoses of the flow-diverter stent in two extremely curved vessels. Strut breaks were observed more frequently using micro-CT (6/84, 7.1 %) than by mammography (4/84, 4.8 %). Histology confirmed all changes of stent architecture. CONCLUSION: Significant changes of stent architecture can be observed and assessed even in the two-dimensional mammographic images. The use of micro-CT is recommended to detect subtle changes like single strut breaks and for three-dimensional information.