Computed Tomography Reference Diameters of the Abdominal Aorta in a Portuguese Hospital Population.

BACKGROUND

Aortic dimensions vary according to age, sex, and population characteristics. This study aimed to establish computed tomography (CT)-based reference diameters for the abdominal aorta in a Portuguese hospital population, providing reference data that may support the assessment of aortic dilatation and future population-specific studies of aneurysm diagnosis and surveillance.

METHODS

A single-center cross-sectional study was conducted using CT examinations performed at a tertiary referral hospital in Portugal during 2018. CT scans were randomly selected using a stratified sampling strategy according to month and time of day. Patients with known aortic disease or CT examinations requested in the context of vascular or cardiac surgery consultations were excluded. Aortic diameters were measured on multiplanar reconstructions using outer-to-outer wall measurements at standardized anatomical locations. Analyses were performed overall and stratified by sex and age group (<50, 50-75, and >75 years). Comparisons were performed using Student's t-test and linear regression models, including age-adjusted analyses for sex comparisons.

RESULTS

A total of 479 patients were included, of whom 266 (55.5%) were males. The mean age was 64.5 years (standard deviation [SD] 17.3). The mean abdominal aortic diameters were 23.71 mm (SD 4.32) at the celiac level, 22.07 mm (SD 4.08) at the superior mesenteric artery level, and 20.95 mm (SD 4.14) at the renal level. Infrarenal diameters ranged from 18.95 mm (SD 4.05) proximally to 17.72 mm (SD 3.89) distally. Men had significantly larger diameters than women at all anatomical locations (all P < 0.001). Aortic diameter increased significantly with age across all segments (all P < 0.001), with consistent and additive effects of age and sex.

CONCLUSION

This study provides CT-based reference values for abdominal aortic diameters in a Portuguese population. Aortic size is strongly influenced by age and sex, supporting the need for population-specific and demographically stratified reference values.