Figure 1. Two-dimensional longitudinal image of common carotid artery (CCA) showing double contour of anterior wall (AW) and posterior wall (PW) ("the double line" sign). The carotid intima- media thickness (CIMT) represents the combined thickness of the hypo-echoic space plus the hyper- echoic line situated towards the interior of the vessel. The measurement could be done at the level of anterior wall (near wall) or at the level of the posterior wall (far wall). See text.
