Intima-media Thickness

Intima-media thickness (IMT), also called intimal medial thickness, is a measurement of the thickness of tunica intima and tunica media, the innermost two layers of the arterial wall. The measurement is usually made by external ultrasound, occasionally by internal, invasive ultrasound catheters, see IVUS, measurements of the thickness of the wall of blood vessels can also be using other imaging modalities.

IMT is used to detect the presence of atherosclerotic disease in humans and, more contentiously, to track the regression, arrest or progression of atherosclerosis. The use of IMT as a non-invasive tool to track changes in arterial walls has increased substantially since the mid-1990s. Although IMT is predictive of future cardiovascular events, the usefulness of measuring change in IMT over time is disputed, as meta-analyses have found that change in IMT is not predictive of cardiovascular events. As such, the use of change in IMT as a surrogate endpoint measure of drug efficacy in clinical trials, or in clinical management of cardiovascular disease, is debated.

IMT is occasionally used in clinical practice, but its role is not clear. After systematically reviewing the evidence base for IMT, the United States Preventive Services Task Force found no support for its routine use in stratification of risk for people at intermediate cardiovascular risk. However, in 2003 the European Society of Hypertension–European Society of Cardiology guidelines for the management of arterial hypertension recommended the use of IMT measurements in high-risk patients to help identify target organ damage and in 2010 the American Heart Association and the American College of Cardiology advocated the use of IMT on intermediate risk patients if usual risk classification was not satisfactory.