Analysis Of Carotid Artery Plaque Echogenicity With Intraplaque Neovacularization Detected With Contrast-enhanced Ultrasound

【Objective】This study applied contrast-enhanced ultrasound(CEUS) technique to obtain the dynamic contrast-enhanced ultrasound imaging of different carotid artery plaque echogenicity, contrast-enhanced intensity visual grading, the contrast parameters and analysis the correlation between echogenicity and the incidence of cerebral vascular events. It will provide the imaging basis to evaluate the stability of carotid atherosclerotic plaque noninvasively and quantitatively.【Methods】1. 39 patients with 64 carotid plaques(31 males, 8 females, average age 66.8±7.4), who visited in my hospital for cervical vascular inspection from September 2013 to February 2015, were enrolled in this study.2. The carotid plaque was examined by TOSHIBA Aplio500 Ultrasonic Diagnostic Apparatus with line array 9L probe and the frequency was between 6.0 and 8.0MHz. Use conventional ultrasound and CEUS to obtain the 2D grey image and the contrast-enhanced dynamic graph of each plaque.3. According to dynamic contrast-enhanced graph, every plaque was analyzed for the contrast parameters and acquired its contrast-enhanced intensity visual grading. Use computer-aided program to obtain GSM of every plaque.4. According to the plaque classification method proposed by Gray-weale et al, the different echogenicity plaques were divided into four groups. The contrast-enhanced intensity visual grading, the contrast parameters and GSM of the four groups of plaques were achieved to analyze their differences.5. Analyze the correlation between the contrast parameters and GSM of these plaques and the incidence of cerebrovascular events of different gray plaques.【Results】1. Compared the GSM among groups: there was statistical difference in the GSM among groups(F=29.365,P<0.001). There was no statistical difference between heterogeneous echolucent plaques and homogeneous echolucent plaques(P=0.245); there were statistical difference between other groups(P<0.05).2. The dynamic contrast-enhanced graphs and the results of visual score of the four groups of plaques: there were statistical difference in the enhanced intensity of Contrast-Enhanced ultrasound enhanced visual score rating of different carotid atherosclerotic plaque echogenicity(c2=17.951,P<0.001).The lower of the plaque echogenicity the visual score of CEUS enhancement will be more obvious. The homogeneous echolucent plaques which scored 2、3 enhancement taken up about 66.7%(14/21) and that is about 92.3%(12/13) in heterogeneous echolucent plaques. The two groups of plaque was most scored 2、3 but there was one homogeneous echolucent plaque with no enhancement; The homogeneous echolucent plaques which scored 1 enhancement taken up about 58.8%(10/17) and that is about 46.2%(16/30) in heterogeneous echogenic plaques. The two groups of plaque were most scored 1.3. Compared the contrast-enhanced ultrasound parameters among groups: the enhanced intensity(c2=29.025,P<0.001) and the enhanced density(c2=30.871,P<0.001) of the four groups of plaques had statistical difference; there was statistical difference between homogeneous echolucent plaques and homogeneous echogenic plaques(P<0.05) or heterogeneous echogenic plaques(P<0.05);there was statistical difference between heterogeneous echolucent plaques and homogeneous echogenic plaques(P<0.05) or heterogeneous echogenic plaques(P<0.05);there was no difference between other groups in statistics.4. Compared the quantitative parameters of visual score rating among groups: there were statistical difference in the enhanced intensity of different grading(c2=23.709,P<0.001).There was statistical difference between grade1 enhancement and grade 2or3 enhancement; there was no difference between other groups in statistics.5. The enhanced intensity and GSM of plaque have a significantly negative correlation(r=-0.376,P=0.000); The enhanced density and GSM of plaque have a significantly negative correlation(r=-0.252,P=0.000).6. The proportion of the incidence of cerebrovascular events in different echoic plaques was 92.9%(13/14) in echolucent plaques, 60%(9/15) in echogenic plaques; the proportion of the incidence of no cerebrovascular events in different echoic plaques was 7.1%(1/14) in echolucent plaques, 40%(6/15) in echogenic plaques.【Conclusions】1. Different gray plaques show different characteristics of CEUS image2. Different carotid artery plaque echogenicity have different value of GSM.3. The visual score of contrast-enhanced intensity and contrast-enhanced parameters can reflect the stability and the degree of intraplaque neovascularization of different gray plaques.4. There was negative correlation between plaque GSM and the contrast-enhanced ultrasound parameters of plaques. Those homogeneous echolucent plaques had high incidence of cerebral vascular events. Our results suggest that the more anechoic lesions and the lower GSM the higher value of contrast-enhanced intensity and enhanced density. It will indirectly suggest that these plaques which have more neovascularization the more unstable and higher incidence of cerebral vascular events.5. CEUS combined with GSM technology can objectively and quantitatively evaluate the formation of intraplaque neovascularization in different echogenicity of carotid artery plaque. It is necessary to have a study on the larger sample size to demonstrate the conclusions of our research because of the small number of each group.