The Pulse Displacement Detection Of The Carotid Artery Vascular Wall Based On The Ultrasound B-Mode Images

With the incidence of cardiovascular and cerebrovascular diseases, disability rate and death rate is increasing year by year.At present, the morbidity, disability and mortality of heart cerebrovascular disease is increasing year by year. Atherosclerosis is regarded as a common pathological basis of this disease. So quantitative analysis of vascular wall stiffness has a great influence on it, which has become a hot spot.In many early onset of cardiovascular disease, clinical practice and experimental study found the marked change of a cardiac cycle artery diameter will directly lead to elastic weakening of the vascular wall. Therefore, the vascular wall pulsation displacement can be acted as an important indicator for diagnosis of the cardiovascular diseases, and also can be used for diagnosis and prediction of heart failure, hypertension, atherosclerosis and other diseases.As one of the main methods of detecting carotid artery pulsation of the vascular wall, clinical ultrasound diagnosis is a non-invasive, cheap, fast and efficient technology, which has the advantages of simple operation, easy to implement, and has no strict requirement for examining the condition and the environment. It's common used in detecting the vascular wall stroke ultrasound displacement image, including B model (B-MODE), M model (M-MODE), echo tracking (ECHO-TRACKING) and so on. Among them,B ultrasound is commonly used in the research and clinical detection, which can extract the vascular wall more accurately and visually. Speckle Tracking method is a classic method based on the ultrasonic image to calculate vascular wall beating displacement. This method mainly uses the normalized cross-correlation matching algorithm to calculate similarity coefficient of vascular wall by extracting carotid artery wall in different time. According to the coefficient, it also can estimate the displacement of the vessel wall. However, the above algorithms have certain requirements for extracting the vascular wall size, and can not detect the vascular wall beating of carotid artery at any position. To solve this problem, proposed byBruce D.Lucas and Takeo Kanade, the Lucas-Kanade optical flow algorithm can calculate the relative motion between the displacement of image pixels. This method is a two frame differential optical flow estimation algorithm by evaluating the deformation between the two images and calculating the two frame to move between each pixel position at the time from t to t+?t. It has been used to evaluate the image pixels between changes.Compared with the speckle tracking method, the optical flow field method can calculate tube wall pulsation in any area of the carotid artery, and can also be used to estimate instantaneous image rate of two-dimensional image or discrete image transfer (you can see the direction of motion of each pixel). However, the maximum displacement curve of the clinical picture is unknown, so it is necessary to establish a theoretical model for reference to analyze the effect of two kinds of algorithms through the theory of displacement Curve and acquire inherent errors of each algorithm. In order to contrast and proof the effectiveness of optic flow field and vascular wall pulsation based on clinical B ultrasound images detecting carotid artery. In order to demonstrate the effectiveness of the optical flow field and speckle tracking, based on clinical B ultrasound images detecting carotid artery, this article deal with the carotid artery simulation and clinical data image by respectively using the above methods, and quantitatively analyze both the results by adopting a set of theoretical image as a reference image and a set of clinical images as the floating image.This article adopt the optical flow method and traditional speckle tracking method to extract the vascular wall pulsation displacement curve. In order to verify the effectiveness of the method, a series of simulation and clinical experiments are carried out.The results show that the simulation experiment this paper can reduce the error in the clinic, and also prove the effectiveness of the optical flow method.The experiment in this article can provide a theoretical basis for the early clinical diagnosis.