Preliminary Assessment Of Motion Dynamic Characteristics Of Common Carotid Artery Wall In Cerebral Infarction Patients By VVI Technique

We measured and analyzed the motion, elastic and their derived parameters of common carotid artery wall in short-axis orientation in normal people and cerebral infarction patients by velocity vector imaging (VVI) technique, and we also studied the characteristics of the parameter curves. On this basis, we compared the two sets of data and combined these new parameters with the previous diagnostic index, so that we could assess the biomechanical state of the vessel wall more comprehensively. We tried to find out some more sensitive indicators for testing atherosclerosis and provide effective clinical basis for cerebral infarction so that we can detect, prevent and treat the disease in earlier time.Part 1. Preliminary assessment of motion dynamic characteristics of common carotid artery wall in normal people by VVI technique[Objective] We applied VVI technique to study and analyze the elastic parameters, motion parameters and their derived parameters in short-axis orientation of the normal carotid artery walls. We also studied the correlation between these parameters and their correlation with age, common carotid artery intima-media thickness and heart rate. This study could provide reference indicators for further study of elastic characteristics of the carotid artery wall in cerebral infarction patients.[Methods] There were 40 normal people in this study, including 21 males and 19 females, whose age were from 28 to 76 years old, their average age is 47.2±12.8 years. At first, we used the high-frequency ultrasound probe under the Carotid VVI observed standard to measure the diameter, intima-media thickness (IMT), observing whether the plaques exist and recorded the heart rate of these people. Then, two-dimensional dynamic images of CCA in 40 normal people were obtained in short-axis view by Simens Acuson Sequoia 512 color Doppler ultrasound. Elastic and motion parameters and their derived parameters were analyzed in right CCA including 6 segments:anterior wall, anterointernal wall, posterointernal wall, posterior wall,posterolateral wall and anterolateral wall. Elastic parameters included systolic maximum tangential strain and strain rate (Smax, SRmax), motion parameters included maximum radial velocity and displacement (Vmax, Dmax). Then we calculated the elastic and motion derived parameters. Elastic derived parameters included the difference between systolic and diastolic maximum tangential strain rate (△SR), time to peak of the Smax and SRmax (SP, SRP) and the pulse wave translation time of strain and strain rate (SPT, SRPT).Motion derived parameters included the difference between systolic and diastolic maximum radial velocity and displacement (△V,△D), time to peak of the Vmax and Dmax (VP, DP) and the pulse wave translation time of displacement (DPT). We studied the characteristics of these parameters and the relationship between these parameters and their influencing factors.[Results] There were no difference in the elastic parameters (Smax, SRmax),in the elastic derived parameters (△SR,SP,SP,SRP,SRPT) and in the motion derived parameters (VP,DPT) among 6 walls (P>0.05). Motion parameters (Vmax,Dmax) and motion derived parameters (△V,△D,DP) of the lateral and anterior wall were higher than those of the posterior and internal wall (P<0.05). Age was negatively correlated with elastic parameters (Smax,SRmax), elastic derived parameters (△SR), motion parameters (Vmax,Dmax) and motion derived parameters (△V,△D).Age was positively correlated with IMT (|r|>0.4, P<0.05). IMT was negatively correlated with elastic parameters(Smax,SRmax), elastic derived parameters(△SR), motion parameters (Vmax,Dmax), motion derived parameters (△V,△D)and Ds-Dd (P<0.05). IMT was positively correlated with elastic parameter SP (r=0.434, P=0.007). Heart rate was positively correlated with elastic parameters (Smax,SRmax), elastic derived parameters (ASR), motion parameters (Vmax,Dmax) and motion derived parameters (△V,△D) (r>0.4, P≤0.01). Heart rate was negatively correlated with elastic derived parameter (SP) and motion derived parameters (VP, DP) (|r|>0.4, P<0.01). Elastic parameters were positively correlated with motion parameters (P<0.05),and positive correlation was also found between time to peak of elastic and that of motion parameters (P<0.001).[Conclusion] VVI is an effective technique for observing carotid artery mechanical characteristics of the movement in normal human, and has potential for studying some of related factors of the characteristics. It can provide some reference indicators for further study of the dynamic characteristics of the carotid artery in cerebral infarction patients.Part 2. Preliminary assessment of elastic characteristics of common carotid artery wall in cerebral infarction patients by VVI technique[Objective] We analyzed the elastic and elastic derived parameters of carotid artery wall in short-axis orientation in cerebral infarction patients by velocity vector imaging (VVI) technique and compared the differences with the parameters of the normal group.[Methods] There were 40 cerebral infarction patients in this study, including 26 males and 14 females, whose ages are from 38 to 78, their average is 56.0±12.4 years. We recorded the plaque formation. The research methods used,the measurement and the elastic parameters were identical with the first part.[Results] Cerebral infarction patients'intima-media thickness (IMT) were significantly thicker than normal people, and their systolic and diastolic diameter difference (Ds-Dd) compared with the normal group significantly reduced (P<0.001). The patients having plaques were obviously more than the control group (There were 28 patients having plaques in carotid artery, and there was no plaque formation in the normal group).The elastic parameters(Smax,SRmax) and the elastic derived parameter (△SR) of the 6 segments in cerebral infarction group were significantly lower than those in normal group (P<0.001). The elastic derived parameters (SRP, SRPT) in anterointernal wall, posterointernal wall and posterior wall of the cerebral infarction group were significantly earlier than those in normal group (P<0.05).[Conclusion] VVI technique can show the elastic characteristics of the common carotid artery wall of cerebral infarction patients.The elastic and elastic derived parameters of cerebral infarction patients significantly reduced compared with those of normal people. Combining these parameters with the traditional detection parameters, we can assess and understand the vascular wall elastic state more comprehensively.