Abstract: Objective To investigate the diagnostic value of Fine-Flow imaging (FFI) combined with ultrasound elastography (UE) for carotid plaque stability in stroke patients. 
Methods In total, 200 patients with ischemic stroke were selected as the observation group, and 200 patients with carotid artery plaques were selected as the control group. Routine grayscale ultrasound was used to observe the characteristics of carotid artery plaques in all patients. FFI technology was used to detect neovascularization in carotid artery plaques, followed by grading of blood flow, and measurement of plaque elasticity parameters using elastography technology. The correlation between the characteristics of carotid artery plaques and ischemic stroke was analyzed and compared between the two groups. Logistic regression analysis was used to study the correlation between relevant indicators and ischemic stroke, providing diagnostic basis for early prevention of patients. Receiver operating characteristic (ROC) curve was drawn to analyze the clinical value of FFI combined with elastography in predicting the occurrence of ischemic stroke. 
Results There were significant differences between the observation group and the control group with respect to age, history of diabetes, history of cardiovascular disease, history of smoking, body mass index (BMI), triacylglycerol(TG), low-density lipoprotein cholesterol (LDL-C), creatinine(Cre), and unstable plaques (P＜0.05). The ratio of region of interest B to region of interest A (B/A ratio) and tissue elasticity score of the observation group measured using ultrasound elastography technology were lower than those of the control group (P＜0.05). The B/A ratio and tissue elasticity score in the unstable plaque group were lower than those in the stable plaque group (P＜0.05). The difference in grading of intraplaque neovascularization between the observation group and the control group was statistically significant (P＜0.05), while the difference in grading of intraplaque neovascularization between the unstable plaque group and the stable plaque group was statistically significant (P＜0.05). The B/A ratio (r=0.791, P＜0.001) and elasticity score (r=0.773, P＜0.001) were positively correlated with plaque stability, while the grading of intraplaque neovascularization (r=-0.270, P＜0.001) was negatively correlated with the stability of plaques. The area under ROC curve (AUC) of neovascularization grading was 0.674, with a sensitivity of 51.6% and a specificity of 75.9%. The AUC of B/A ratio was 0.822, with a sensitivity of 77.4% and a specificity of 86.2%. The AUC of combination of the two indicators was 0.864, with a sensitivity of 80.6% and a specificity of 86.2%. 
Conclusion By evaluating the stability of plaques, ultrasound FFI technology combined with elastic imaging technology can be used to predict the risk of ischemic stroke in an early stage, and provide diagnostic basis for clinicians to take early intervention measures to reduce the incidence of ischemic stroke. 

Key words: ischemic stroke, Fine-Flow imaging, carotid artery plaque