Reproducibility of sonographic measurements of carotid intima-media thickness

BACKGROUND: Carotid intima-media thickness (IMT), measured with B-mode ultrasound, is a marker for atherosclerosis and widely used as an outcome in intervention trials. PURPOSE: To evaluate the reproducibility of carotid intima-media thickness measurements using tissue harmonic imaging (THI) sonography between two observers with different levels of experience. MATERIAL AND METHODS: IMT measurement was performed in 40 patients: 26 males and 14 females, with a mean age of 62.6 years. The measurements were taken on the posterior wall of the right common carotid artery using a standardized protocol. Observer measurement of the IMT was independent and blind. Statistical analysis was done with parametric tests and Pearson's correlation coefficient. RESULTS: The measurements of the IMT were taken satisfactorily in all cases. IMT measurement time was 5 min/study. No significant differences were noted between the means obtained by the two observers. The interobserver correlation of the measurements was very high (97.2%). CONCLUSION: The results of this study show that carotid IMT measurement using THI sonography and a standardized protocol is accurate and reproducible.