Application of high-resolution cone-beam computed tomography for evaluation of endothelialization after flow diverter implantation for unruptured intracranial aneurysms.

Background and purpose: Although high-resolution cone-beam computed tomography (HR-CBCT) is used for immediate evaluation of stent apposition, studies using this technique to evaluate flow diverter (FD) endothelialization during follow-up are limited. The study aims to investigate the potential of HR-CBCT in assessing FD endothelialization and identify factors influencing poor endothelialization.

Materials and methods: The clinical and imaging data of patients with unruptured intracranial aneurysms (UIAs) treated by FDs from March 2019 to October 2023 were retrospectively analyzed. HR-CBCT was used for immediate evaluation of stent apposition, and FD endothelialization at 3-, 6-, and 12-months post-implantation was evaluated using HR-CBCT and digital subtraction angiography. Multivariate logistic regression analysis was used to identify factors associated with poor endothelialization.

Results: Among 402 FDs implanted for 446 aneurysms in 378 patients, 41 showed incomplete stent apposition (ISA) in post-implantation HR-CBCT scans. The aneurysm-occlusion rate at 12 months post-implantation was 84.8% (378/446), with 8.7% (35/402) of the FDs exhibiting in-stent stenosis (ISS). At 12 months post-implantation, 343 (85.1%) FDs showed good endothelialization, while 59(14.9%) exhibited poor endothelialization. Multivariate logistic regression analysis identified age ≥ 60 years (OR=2.209;95% CI:1.053-4.635;P=0.04), a large aneurysm lumen inflow angle (OR=1.102;95% CI:1.071-1.135;P<0.001), parent artery excessive tortuosity (OR=9.402;95% CI:1.141-77.479;P=0.04), and ISA (OR=10.967;95% CI:4.290-28.035;P<0.001) as independent risk factors for poor endothelialization.

Conclusions: HR-CBCT can accurately evaluate FD endothelialization and ISS of UIAs after FD implantation. Age ≥ 60 years, a large aneurysm lumen inflow angle, parent artery excessive tortuosity, and ISA are independent risk factors for poor endothelialization.

Abbreviations: HR-CBCT = high-resolution cone-beam computed tomography; FD = flow diverter; UIAs = unruptured intracranial aneurysms; ISA = incomplete stent apposition; ISS = in-stent stenosis.