A Cross-Sectional Analysis of Vascular Geometry in Adults: Associations of Age and Biological Sex with Iliofemoral Arterial and Venous Tortuosity

Iliofemoral vascular tortuosity may reflect vascular aging, yet natural anatomic variation remains poorly characterized at scale. In this single-center retrospective study, we quantified arterial and venous iliofemoral tortuosity in a large cohort of adults with contrast-enhanced abdominopelvic computed tomography (CT) scans. Using an nnU-Net-based deep learning pipeline, iliofemoral arteries and veins were segmented from CT images. Representative centerlines were extracted and mean centerline curvature was computed to quantify tortuosity. Primary analyses explored associations of arterial and venous tortuosity with core covariates: age, biological sex, race, body mass index, height, and smoking status. Secondary analyses evaluated associations with clinical comorbidities and medication exposures. Complete-case analytic cohorts included 725 patients for arterial analyses and 718 for venous analyses. After adjustment for core covariates, age was positively associated with both arterial and venous tortuosity, with a stronger association for arteries than veins (+15% vs +6% per decade). Tortuosity variability among the cohort was higher for arteries than veins (2.2-fold higher residual variance). Female sex was associated with lower arterial and venous tortuosity. Traditional atherosclerotic risk factors, including hypertension, hyperlipidemia, and diabetes, were not associated with iliofemoral tortuosity. After adjustment for co-occurring conditions, end-stage renal disease was associated with lower arterial and venous tortuosity, and congestive heart failure was associated with lower venous tortuosity. Connective tissue disease was associated with higher venous tortuosity. These findings demonstrate distinct arterial, venous, age-related, and sex-related patterns of iliofemoral tortuosity. Additionally, they provide morphometric context for studies evaluating large-vessel geometry and vascular stiffness, hemodynamics, and disease-specific procedural outcomes.