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

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