Contrast-Enhanced Ultrasound Feasibility in Assessing Carotid Plaque Vulnerability—Narrative Review

Figure 3. Carotid atherosclerotic plaques exhibit diverse surface morphologies, including smooth, irregular, or ulcerated. In accordance with CEUS imaging, smooth (a) denotes a regular plaque surface devoid of significant irregularities. Irregular plaques (b) are characterized by surface fluctuations ranging from 0.3 to 0.9 mm. Ulceration (c) represents the most severe irregularity, featuring a cavity measuring at least 1 × 1 mm in size (marked with an asterisk).

Figure 1. Hypoechoic plaques (types 1 and 2 in Gray–Weale–Nicolaides classification) are associated with intraplaque hemorrhages and lipid accumulation. Type 1 (a) is uniformly echolucent and mainly composed of lipid and necrotic components (plaque is marked with an asterisk). Type 2 (b) is predominantly echolucent, with small areas of echogenicity caused by calcifications.

Figure 2. The figure illustrates the qualitative grading system used to assess intraplaque neovascularization within carotid plaques. Grade 1 (a) is given to carotid plaques that show no moving microbubbles within the plaque or if there are any, they are limited to the nearby adventitial layer. It is important differentiate artifacts induced by calcification with contrast enhancement (blue arrows). Grade 2 (b): there is moderate visibility of moving bubbles within the plaque, mostly at the adventitial side or plaque shoulder. Grade 3 (c): there is a clear and visible presence of bubbles moving towards the plaque core or diffused enhancement.