Tracking Algorithm And Strain Calculations Based On Mr Images Of Left Ventricular Tag Line

Using tagged Magnetic Resonance (MR) images, we can research deformation and motion of the heart muscle. The motion information of the Left Ventricle (LV) can reflect the pumping function of the heart, which can be used to diagnose many heart diseases. Therefore, analyzing motion of LV has become a hotspot in the relative researching filed. In this paper, we focused on the research of tracking tags and the strain calculation algorithm based on the Magnetic Resonance left ventricle image. Based on the previous research, our work could be divided to two parts as below:(1) Classification of tag intersections. In order to better detect and track tags, we adopted the support vector machine to classify all the girding intersections into two categories: points on the cardiac muscle and points not on the cardiac muscle at first, according to the extracted texture character by LM filter bank. We also discussed how to extract the combined characters separately using Principal Component Analysis (PCA) and Canonical Correlation Analysis (CCA). The result indicates that the support vector machine has better veracity when using the combined characters, and CCA is better than PCA when extracting combined characters.(2) Tracking tags. We adopted deformed grid model to track tag points with different energy formulation designed to two kinds of points according to the physical character of the heart motion. We use the greedy algorithm to get the optimized result. In the process of tracking tags, we first track the points on cardiac muscle and then the other points, which is different from other algorithm flows. The experiment demonstrates that different kind of tag points tracked with different energy formulation assigned to them is reasonable and effective and the tags could be tracked correctly with little time consuming.(3) Strain calculation. On the base of tag point tracking result, we use the mesh free algorithm, a method in mechanics area, to calculate the strain of left ventricle. First, moving least square approximation is been used to two-dimensional motion reconstruction and then the derivative of the shape function help use to get the strain situation of the left ventricle. Mesh free algorithm is a novel method used in the heart strain calculation. The experiment demonstrates that the method could control the error in an acceptable scope.