Individual measurement and significance of carotid intima, media, and intima-media thickness by B-mode ultrasonographic image processing.

OBJECTIVE: We assessed the clinical significance of intima (IT), media (MT), and intima-media (IMT) thickness of the common carotid artery using B-mode ultrasonographic image processing. METHODS AND
RESULTS: One hundred seventy consecutive patients underwent common carotid artery scanning using high-resolution ultrasonography. A total of 150 patients could be analyzed off-line using ultrasonographic image processing, devised for individual measurement of IT, MT, and IMT. By univariate analysis, IT (range, 0.27 to 0.41 mm) was associated with age, whereas MT (range, 0.27 to 0.74 mm) and IMT (range, 0.49 to 1.12 mm) were associated with age, fibrinogen, and creatinine. Among atherosclerosis risk factors, hypertension was associated with thickness of all 3 layers, whereas smoking was associated with IT only. By multivariate analysis, IT was associated with age, hypertension, and smoking, whereas MT and IMT were associated with age, hypertension, and blood urea nitrogen level.
CONCLUSIONS: Carotid IT is associated with smoking, whereas age and hypertension are associated with thickness of all 3 arterial layers. Our results suggest a differential response of the vasculature to systemic risk factors.