EVALUATION OF THE CAROTID-ARTERY INTIMA-MEDIA-THICKNESS - INFLUENCES OF DIFFERENT METHODS, CHARACTERISTICS OF THE SUBJECTS, AND INVESTIGATORS

Comparison of two different methods for the measurement of the common carotid artery intima-media thickness (IMT) regarding results and repr oducibility, and investigation of the influence of the subjects charac teristics on the results. Method: 20 healthy subjects were studied (6 men, 14 women, mean age 27.4 +/- 4.4 years). B-Mode pictures were take n of the carotid arteries on both sides (longitudinal sections from ve ntral and lateral) and stored for measurement either in systole or in diastole. Maximum IMT was measured conventionally by manual setting of calipers (method 1), the mean IMT over a length of 1 cm was calculate d from the area of the intima plus media by means of a computer (metho d 2). 10 subjects were studied twice for the evaluation of intra- and interobserver variability. Results: Mean IMT was between 0.48 +/- 0.07 mm (method 1/observer 1) and 0.55 +/- 0.07 mm (method 2/observer 2), IMT values resulting from method 2 had a better correlation in repeate d measurements (coefficient 0.84/0.93 for inter/lintraobserver compari son) than those resulting from method 1 (0.79/0.67). Age and height we re significantly correlated with IMT (coefficients 0.53 and 0.52 for m ethod 2), no correlation was found for body weight, BMI, sex or years of smoking. There was a significant inverse correlation between blood pressure and IMT (-0.21 to -0.32). Conclusion: In younger healthy subj ects, the results of IMT measurement are influenced by age, height and actual blood pressure. The values resulting from both methods are com parable, whereas method 2 has a better reproducibility.