Vertebral Artery Doppler Reference Values in Healthy Turkish Adults: Influence of Age, Sex, and BMI

Objective: To establish population-specific bilateral reference values for vertebral artery (VA) diameter, peak systolic velocity (PSV), enddiastolic velocity (EDV), resistive index (RI), pulsatility index (PI), and flow volume in healthy Turkish adults, and to assess the effects of age, sex, laterality, and body mass index (BMI) on these parameters.Methods: This prospective, multicenter study enrolled 223 healthy Turkish adults from three centers.VA Doppler ultrasonography was performed using a standardized protocol.The measured parameters included VA diameter, PSV, EDV, RI, PI, and flow volume.Results: Left vertebral arteries exhibited significantly larger diameter (3.73 ± 0.57 mm vs. 3.52 ± 0.61 mm), PSV, EDV, and flow volume compared to the right side (P < 0.05).Males had a larger right VA diameter and higher RI and PI bilaterally, whereas females had higher right VA EDV (P < 0.05).Age was negatively correlated with PSV, RI, and PI, but positively correlated with left VA diameter.BMI was negatively correlated with PSV, RI, and PI, but did not significantly affect flow volume.Reference percentiles were established based on sex and age.Conclusion: This study investigated normal reference values for six VA Doppler parameters in 223 healthy Turkish adults, stratified by sex and age, with BMI evaluated as a covariate.It is the first study to include BMI as a covariate and to derive percentile-based norms from a multicenter Turkish cohort.The normal range (5 th -95 th percentile) for total VA flow volume was 124.7-391.8mL/min.Because this lower limit lies well below the widely quoted 200 mL/min threshold for vertebrobasilar insufficiency, applying that threshold would misclassify a considerable proportion of healthy adults as abnormal.These findings support improved clinical interpretation of VA Doppler ultrasonography.