The Research Of Image Registration Method For K-t Accelerated Cardiac Magnetic Resonance Imaging

Magnetic resonance imaging technology,as one of the methods used for the detection of cardiovascular diseases,because of its advantages in the aspect of cardiac function detection,has been given more and more attention.But owing to the limitations of human physiology and physics,at the same time can only be collected one Fourier coding coefficient of images,so imaging speed is show.A number of studies devoted to improve the speed of magnetic resonance imaging,based on k-t imaging techniques,such as k-t SENSE and k-t PCA,using imaging sequences on the redundancy of time dimension,can increase the sampling speed ratio to more than eight times.Due to they use time redundancy of imaging sequences,so it is particularly sensitive to which imaging object includes movement,can't remove the artifacts that movement caused,resulting in the reconstructed image fuzzy in the spatial domain.In order to make the standard based on k-t imaging techniques to be used in imaging objects with large movement of the occasion,and improve the applicability of the MRI technology,proposed an improved image registration method,through multi-step registration process to obtain the movement information of the heart.In terms of extract the heart local image sequence,using the characteristics of cardiac magnetic resonance images,first calculate the standard deviation of image sequences,then using the method of image segmentation to obtain the largest part of all the areas that is the heart part;In specific registration,choose the similarity measure function based on mutual information,bilinear interpolation and One Plus One Evolutionary optimization method,approximate to the movement of the heart into affine ransformation,followed by multi-step affine transformation model registration method which contains translation transformation,rigid transformation and affine transformation to complete the registration process from coarse to fine;Finally about registration of images sequence,using the adjacent two image registration,obtaining a series of transformations relationship,then replacing the transformations relationship into that relationship between the first image from front to back in sequence,according to thetransformations relationship can complete the registration process.Through theoretical analysis and experimental results show that the multi-step affine transformation model registration method can obtain the movement information of the heart to a certain extent,and get higher precision than the traditional affine transformation model registration method.