Carotid intima-media thickness measurements: Techniques and clinical relevance

Atherosclerosis is a systemic disease that is responsible for most cardiovascular events and stroke. Epidemiologic studies and intervention trials based on the incidence of acute vascular disease end points require years of follow-up, the participation of large populations, or both. As a consequence, such studies consume considerable time and financial resources. The use of surrogate markers, therefore, is of paramount relevance because it allows researchers to have reliable data in less time and from reduced populations. Intima-media thickness (IMT) measured by B-mode ultrasound is the most studied surrogate marker and has been validated by official medical agencies. In this article, we review the most important technical considerations related to its measurement and highlight issues that should be systematically addressed in IMT-related studies. In summary, the use of IMT as an end point in clinical studies is of great value, but several technical limitations might jeopardize its interpretation.