How aneurysm shape affects occlusion success after flow diverter placement

Flow Diverters (FD) are an established endovascular treatment for intracranial aneurysms, but complete aneurysm occlusion remains a challenge. This study aimed to quantitatively analyze three-dimensional aneurysm morphology and assess its influence on the likelihood of total occlusion after FD placement.

For this single-centre study we retrospectively included patients with unruptured intracranial aneurysm treated with FD between 2019 and 2022. The study group comprised patients with incomplete occlusion at first follow-up (~ 6 months). The control group, matched for common risk factors, included patients with complete occlusion. Based on 3D reconstructions, we calculated quantitative parameters: mean and entropy of mean and Gaussian curvature, mean and entropy of Writhe number, and Zernike Moment Invariants energy.

Thirty-five patients met study group criteria and 38 were included in the control group. Mean age was 57.6 ± 12.2 years and females comprised 82.9% and 81.6% of the groups, respectively. Incompletely occluded aneurysms showed higher Aspect Ratio (1.34 ± 0.42 vs. 1.29 ± 0.51; p = 0.03) and Size Ratio (1.28 ± 0.28 vs. 1.21 ± 0.28; p = 0.04), greater Gaussian curvature entropy (4.03 ± 0.60 vs. 3.73 ± 0.62; p = 0.03), and higher Zernike Moment Invariants energy (545.6 ± 256.2 vs. 271.6 ± 126.2; p = 0.03). In multivariate logistic regression, Gaussian curvature entropy (OR = 2.06; 95% CI: 1.26-13.71; p = 0.04) and Zernike Moment Invariants energy (OR = 3.02; 95% CI: 1.35-9.19; p = 0.02) were independently associated with incomplete occlusion.

Quantitative descriptors of aneurysm dome morphology, particularly Gaussian curvature entropy and Zernike Moment Invariants energy, may influence the likelihood of complete occlusion following FD placement.