Prediction for rupture risk of carotid artery plaques: A comparative study of 3D-GSM and CAS system.

PURPOSE: The study aimed to explore whether GSM based on 3D-ultrasound could predict rupture of carotid plaques and to quantitatively evaluate the vulnerability of carotid plaques.

MATERIALS AND METHODS: 22 Patients with carotid plaques enrolled received 3D-US and 3.0T MRI examinations with intervals less than 48h. Images from two modalities were compared plane by plane. Based on the MRI analysis of plaques tissue compositions, images were divided into 4 groups: fibrous group, lipid core group, calcification group and hybrid group. GSM differences among groups were analyzed and 95% CI was calculated. Based on CAS(carotid atherosclerosis score)system, MRI images were divided into low risk group, medium-low risk group, medium-high risk group and high risk group. GSM differences were compared among groups and 95% CI was calculated. The correlation between GSM and LRNC% (lipid-rich necrotic core%) was analyzed in medium-high risk group and high risk group. Coefficient of variation(CoV) was used to compare the reproducibility of GSM in calcification group and lipid core group.

RESULTS: A total of 164 images were matched between 3D-US and MRI. In the classification of plaque tissue composition, GSM was the highest in calcification group (n=29, 95%CI: 57.28-70.38) with a significant difference from other groups, whereas the lowest in lipid core group (n=78, 95% CI:41.79-49.36), but with no significance compared with the fibrous group and hybrid group. In CAS system, GSM was the lowest in high risk group (n=19, 95% CI: 26.44-36.56) and there were significant differences among each group (p<0.05). In high risk group and medium-high risk group, GSM was negatively correlated with lipid core ratio (r=-0.46, p=0.003). CoV of GSM in the calcification group(10.87%) was better than in lipid core group(13.02%), both of them were acceptable.

CONCLUSION: GSM obtained by 3D-US VPQ could evaluate the plaque vulnerability and be served as a new promising method to predict plaque rupture.