Carotid intima-Media Thickness and Plaque

Ultrasound imaging of the far wall of the common carotid artery produces two hyperechoic parallel lines: the carotid intima-media thickness (c-IMT) corresponds to the inner and outer echogenic lines.

Histologic studies have validated these lines as the lumen-intima interface and the media-adventitia interface.

The rationale of this ultrasound-based measurement is that the c-IMT is an indicator showing essential information in the very early phase of degradation, and is an independent risk factor for myocardial infarction and stroke.

The measurement of c-IMT may be with manual or methods or with automated systems: the manual measurements require rigorous quality control and are more observer dependent than automated systems.

The plaques are focal structures encroaching into the arterial lumen of at least 0.5 mm or 50% of the surrounding IMT value, or demonstrates a thickness >1.5 mm as measured from the intima-lumen interface to the media-adventitia interface.

Several studies have indicated that plaque information relates more strongly to future cardiovascular events than c-IMT, and it is increasingly clear that c-IMT and plaque are biologically and genetically distinct phenotypes of atherosclerosis.

In this lesson the methodology of the echocolor Doppler study of c- IMT is presented.

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