Strain analysis of intracranial aneurysms for characterization of irregular pulsation from 4D-CT angiography

Intracranial aneurysm is a life-threatening cerebrovascular disease. Recent studies have shown that irregular pulsations are associated with an increased risk of rupture. Currently, there is an urgent need for an objective and real-time method for analyzing wall deformation associated with irregular pulsations. In this study, we developed a fast and robust analytical framework based on an improved Horn-Schunck optical flow method. Verification experiments demonstrated that the proposed method exhibited sufficient accuracy and robustness. Patient-specific deformation analysis showed that irregular pulsation sites exhibited higher displacement and strain values compared with other regions of the aneurysm surface. The maximum first principal strains were significantly higher in intracranial aneurysms with irregular pulsation than in those without irregular pulsation (0.26 [0.20-0.28] vs. 0.19 [0.18-0.20], p=0.032; Wilcoxon rank-sum test). Overall, this framework can objectively identify irregular pulsations during the cardiac cycle and offers straightforward, user-friendly applicability for clinical diagnosis.