To investigate the application value of ultrasound real-time tissue elastography technology (RTE) in the detection of the vulnerable carotid atherosclerotic plaques.

The carotid atherosclerosis models (CAS) of rabbits were established by high fat feeding combined with air drying technique treatment in 15 healthy male large-ear rabbits weighting 2-2.5 kg. The plaques were classified into 4 types based on the conventional ultrasound analysis and the elastic hardness index. The hardness ratio of plaque in each type was further analyzed by using RTE technique. Then the correlations between the conventional ultrasound classification and elastic parameter and histological type were analyzed.

28 CAS models were successfully established from the 15 rabbits, among them 34 of the 51 plaques were included in this investigation. A positive correlation (r=0.602, P<0.01) of plaques classified by ultrasound and their pathological types was observed in all the four groups. The positive correlations (r=0.538, 0.563, both P<0.01) between the conventional ultrasound classification and the elastic hardness index and the hardness ratio were also detected. In terms of plaque elastic hardness index, no significant differences between Group Ⅰ and Ⅱand group Ⅱ and Ⅲ were detected. However, there were significant differences in other comparisons: Ⅰ vs Ⅲ, Ⅰ vs Ⅳ, Ⅱ vs Ⅳand Ⅲ vs Ⅳ group (t=2.25, 2.08, 2.95, 2.57, all P<0.05). In comparison of the hardness ratio, no difference was detected between group Ⅰ and group Ⅱ. However, there were significant differences among the other groups: Ⅰ vs Ⅲ, I vs Ⅳ, Ⅱ vs Ⅲ, Ⅱ vs Ⅳand Ⅲ vs Ⅳgroup (t=2.66, 2.91, 2.45, 2.60, 2.12, all P<0.05).

RTE technology can be used to quantify plaque characteristics by using the elastic parameters, which may indirectly reflect the pathological structures of plaques, probably providing a useful index for assessment of vulnerable plaque.