VVI allows to assess multi-dimensional regional mechanics of carotid wall.

Objective: to investigate the mechanical properties of carotid plaques.

Methods: Study population consisted of 7 patients (aged 60–78, median-63) with AIS. Circumferential and longitudinal strain (Sc, Sl) and strain rate (SRc, SRl) were calculated for plaques (separately in three points for cap, core and base) and for plaque-free area for each patient. Plaque characteristics (echogenicity, length, degree of stenosis) were assessed.

Results: Both Sc and SRc were higher in all parts of carotid plaque in comparison with plaque-free area and the difference was significant for cap and core. (SRc values were 0,71±0,32, 0,92±0,35 and 0,66±0,36 for plaque cap, core and base respectively and 0,49±0,24 for plaque-free area). We observed a significant difference in SRc and SRl between plaque core and values for base and cap (SRl was 0,86±0,45 for core vs 0,45±0,27 and 0,49±0,27 for base and cap respectively, p<0,05). This difference was more marked in low-echogenic plaques and no difference was detected in hyper-echogenic, calcified plaques. Correlation analysis revealed moderate negative correlations between plaque length and SRc for cap (r=−0,37) and base (r=−0,44) (but not for core). No significant correlations were found between plaque mechanical properties and degree of stenosis.

Conclusions: Plaque formation leads to the alteration of the elastic properties of the carotid arterial wall. The inner part of plaque is more mobile in comparison with the plaque cap and base, especially in low-echogenic plaques. The increased mobility of the plaque core may be linked with plaque vulnerability.