Abstract Number: Esoc2026a579 Positional Changes of the Proximal Internal Carotid Artery: A Hospital-Based Retrospective Cohort Study

Abstract Background and aims The position of the internal carotid artery (ICA) within the peripharyngeal spaces may change over time. Particularly, a retropharyngeal ICA, as a specific vascular variant, demands caution during pharyngeal procedures. Longitudinal data regarding these positional changes and their underlying factors remain limited. This study aims to characterize serial positional changes of the ICA in this region and to identify associated factors. Methods This study included patients with ≥2 neck computed tomography angiography (CTA) scans (interval ≥12 months) between 2019 and 2025. Morphological features of the C1 segment and positional parameters (including the ICA–external carotid artery (ECA) angle on the axial plane, axial rotation of the carotid bifurcation, and ICA position within the peripharyngeal spaces) were assessed at each time point. Ordinal logistic regression was performed to identify risk factors associated with retropharyngeal ICA. Results Among 294 patients (594 CTA scans; mean age 65.0 ± 13.1 years; 61.9% male), altered axial rotation of the carotid bifurcation occurred more frequently on the right side (71.8%, p = 0.003). Older age (OR = 1.05 per year, 95% CI: 1.03–1.07, p 0.001) and female sex (OR = 1.83, 95% CI: 1.13–2.95, p = 0.013) were associated with a higher ICA position grade within the peripharyngeal spaces. Conclusions The position of the periopharyngeal ICA is dynamic, with changes more frequently on the right side. Older age and female sex are independent predictors of a higher ICA position grade within the peripharyngeal spaces. Conflict of interest Anling Luo: nothing to disclose. Juan Wen: nothing to disclose. Xuzi Li: nothing to disclose. Yiting Deng: nothing to disclose. Qin Yang: nothing to disclose. Li He: nothing to disclose. Muke Zhou: nothing to disclose. Figure 1 - belongs to Background and aims Figure 2 - belongs to Results Figure 3 - belongs to Conclusions