Purpose Incomplete stent apposition can lead to thromboembolic complications or post treatment endo-leak when a flow diverter (FD) stent treatment is performed. To facilitate the assessment of stent apposition during the procedure, a new imaging technique using a combination of high resolution cone-beam CT (CBCT) was developed. The purpose of this study is to review a series of large/giant aneurysm patient who underwent FD treatment, and evaluated using this new imaging method.
Methods A total of 6 large/giant cavernous internal carotid artery (ICA) aneurysms were treated with a Pipeline stent. The procedures were performed using an angiosystem called Artis Q biplane (Siemens Healthcare GmbH, Forchheim, Germany). Immediately after the stent deployment, a 20 s high-resolution CBCT without contrast injection was performed followed by high resolution 6 s CBCT with contrast injection. The two acquisitions were then fused using a function called “identity mapping” to adjust the misalignment that occurs during the fusion process. After adjusting the window level to minimize inter-observed variability, volume rendering images of the treated vessel were created, and combined with the image of the deployed stent. If the post processing images revealed incomplete stent apposition, a stent-plasty using a super compliant balloon was performed. The quality of the CBCT images were retrospectively assessed. For those who underwent stent-plasty, the apposition/shortening of the delivered stent before and after the plasty were analyzed.
Results All 6 patients successfully underwent the CBCT acquisitions immediately after the stent deployment. In all patients, the post reconstruction VR images clearly visualized the 3D structures of both stent and parent artery. Three patients showed incomplete stent apposition in the post processing images and consequently underwent stent plasty followed by another CBCT acquisitions. For these, the final CBCT images showed improved stent apposition with profound shorting of the stent. There was no symptomatic adverse event after the procedure. In four patients, the MRI performed the day after the procedure showed asymptomatic multiple DWI positive lesions, all of which disappeared in the 3 month follow up MRI.
Conclusions The combination of high resolution CBCT acquisitions provided clear visualization of 3D structures of both stent and parent artery after the FD treatment. This imaging modality may contribute to the better understanding of stent apposition after the FD treatment.
Disclosures I. Yuki: 1; C; Siemens Research Grant. T. Ishibashi: None. C. Dahmani: 5; C; employee : Siemens Healthcare Japan. Y. Abe: None. S. Hataoka: None. A. Ikemura: None. I. Kan: None. Y. Murayama: 1; C; Siemens Research Grant. 2; C; Stryker Japan.