Standardized ultrasound protocol, trained sonographers and digital system for carotid atherosclerosis screening

Carotid intima-media thickness (IMT), a valid measure of atherosclerotic disease, has been proposed to be included in the algorithms for cardiovascular risk stratification. However, assessment of carotid IMT is still not easily performed in an office setting. In the present study, we evaluated the reproducibility of a standardized protocol for carotid artery atherosclerosis screening.

Carotid arteries of 30 patients were scanned twice (interval 1-10 days) by six trained sonographers, using portable ultrasound systems. A screening protocol was adapted from methods used in clinical trials in which carotid IMT was the primary outcome measure. To test the reproducibility of the method, variability between the two scans was analyzed.

A high level of agreement was found between the scans for measurement of mean common carotid IMT [mean difference S0.002, 95% confidence interval (CI) S0.011 to 0.006, PU0.435], maximum region common carotid IMT (mean difference S0.002, 95% CIS0.017 to 0.014, PU0.779) and mean maximum IMT including the common, bifurcation and internal carotid arteries (mean differences 0.021, 95% CI S0.006 to 0.047, PU0.166). No significant differences were found between scans with regard to the average number of carotid segments visualized, the number of atherosclerotic plaques or plaque burden.

Reliable IMT measurements can be obtained using a standardized protocol performed by trained sonographers using a digital portable ultrasound system in an office setting.