Carotid plaque rupture is closely associated with the degree of neovascularization within the plaque. Recently, the presence of intraplaque neovascularization was demonstrated using contrast-enhanced ultrasound (CEUS) . We investigated the histopathologic findings of enhanced plaque on CEUS in patients who were undergoing carotid endarterectomy (CEA). Between April 2009 and May 2011, we enrolled consecutive 18 patients (16 men, age 69·4 ± 6·7years) who were undergoing CEA. We performed CEUS in all patients before CEA and investigated the association between ultrasound imaging and histopathology of specimens. Sonazoid (Daiich-Sankyo, Tokyo, Japan), perflurobutane microbubbles, was used as the contrast agent. CEUS revealed enhanced plaque in 11 (61·1%) of 18 patients. Enhanced plaque was classified into two sub-groups: a spotty pattern as moving bright spots within plaque; and a linear pattern, where enhanced lesions appeared as a line from intima into plaque (Fig. 1). Only a spotty pattern was observed in five patients, whereas both a spotty and linear pattern were observed in six patients. The amount of neovascularization was larger in enhanced than in non-enhanced plaque (6·79 ± 5·17/2·5 mm2 vs. 1·12 ± 0·90/2·5 mm2, P = 0·001). Furthermore, the enhanced group had more macrophage aggregation (7·76 ± 3·70% vs. 4·23 ± 1·63%, P = 0·030) and intraplaque haemorrhage (18·84 ± 14·88% vs. 5·52 ± 9·68%, P = 0·013) compared with the non-enhanced group. Thin fibrous cap (<200 μm) was more frequent in enhanced than non-enhanced plaque (100% vs. 28·6%, P = 0·002). All of the enhanced plaques with a linear pattern had fibrous cap rupture, but this was observed in only 20% of those with a spotty pattern (P = 0·015). Enhanced plaque on CEUS indicates vulnerable plaque. A linear pattern of enhanced plaque indicates plaque rupture. Enhanced plaque on CEUS should become a new surrogate marker of vulnerable carotid plaque.