Assessment of Inter-Observer Variability, Cardiac Cycle and Gender Influence on Carotid Intima-Media Thickness Measured Using Ultrasound in Healthy Adults

Background : Carotid intema-media thickness (cIMT) is a widely utilized noninvasive marker for assessing early atheroscelorosis and cardiovascular risk. cIMT is commonly measured using B-mode ultrasound; however, several factors can introduce variability, including the cardiac cycle phase (systole vs. diastole) and interobserver differences. This study aims to evaluate the inter-observer variability in cIMT measurements and to determine differences in cIMT across genders, cardiac cycle phases, and contralateral carotid arteries. Methods: cIMT measurements were obtained using B-mode ultrasound from 50 healthy adults (25 males, 25 females) bilaterally during both systolic and diastolic phases. Two independent operators performed the measurements to assess inter-observer variability using the intraclass correlation coefficient (ICC) and Bland-Altman analysis. Gender differences, cardiac cycle phase effects, and differences between contralateral sides were analyzed using paired t-tests. Results: A total of 200 cIMT measurements were analyzed. Inter-observer agreement was moderate (ICC = 0.68) with a small bias (-0.02 ± 0.05 mm). Males exhibited significantly higher cIMT than females (mean difference = 0.08 mm, 95% CI 0.07–0.10, p < 0.001). No significant differences were found in cIMT between systolic and diastolic phases (p = 0.51) or between right and left carotid arteries (p = 0.70). Conclusion: The study demonstrates moderate inter-observer variability in cIMT measurements using B-mode ultrasound. Gender significantly influences cIMT, with males having thicker cIMT compared to females. However, no significant differences were observed between cardiac cycle phases or between contralateral sides of the carotid arteries.