A Research Of Intensity Inhomogeneity Correction In Magnetic Resonance Image Based On Multicoil Imaging

Magnetic resonance imaging(MRI)is a medical imaging technique that is widely used for medical diagnosis based on the principle of nuclear magnetic resonance.However,there is a phenomenon of intensity inhomogeneity in MR images.Among them,the intensity inhomogeneity in the single-section MR image is mainly caused by the inhomogeneous signal received by the surface coil,while the intensity inhomogeneity in the multi-section MR image is not only affected by the above factor,but also affected by the intensity difference between images and the fusion of overlapping regions between adjacent images.The intensity inhomogeneity in the MR image will affect the subsequent processing of the image and even the accuracy of clinical diagnosis.In recent years,sources of intensity inhomogeneity in the MR image have been studied extensively,and lots of algorithms have been proposed for the intensity inhomogeneity correction.In this paper,we have proposed corresponding solutions to solve the problems existing in the intensity inhomogeneity correction methods of the single-section MR image and the multi-section MR image.1、In intensity inhomogeneity correction methods of the single-section MR image,the method that based on low-resolution body coil image to correct the surface coil image can achieve better results.However,this method requires to scan MR images twice,which increases the scanning time.To solve this problem,this paper proposes a solution which uses the body coil and the surface coil as the receiving coil to collect MR signals.In this method,the first step is to reconstruct the collected magnetic resonance signal,so as to obtain the corresponding the body coil image and surface coil image,which have the same resolution and tissue position.Secondly,the body coil image and the surface coil image are filtered using BM3 D denoising algorithm with adaptive threshold.Finally,based on the polynomial surface fitting algorithm,the surface coil image is corrected by using the body coil image,which is homogeneous in the intensity distributions.The method proposed in this paper not only has better intensity inhomogeneity correction result,but also reduces the scanning time of MRI.2、The existing intensity inhomogeneity correction methods of the multi-section MR image mainly use histogram matching or histogram registration to eliminate the intensity difference between images,which destroys the contrast between tissues.Tosolve this problem,based on the characteristic of intensity homogeneity of the body coil image,this paper proposes a method to correct the stitching surface coil image by using the stitching body coil image.In this method,firstly,the image stitching algorithm based on SIFT feature detection is used to stitch body coil images and surface coil images respectively.Then based on the polynomial surface fitting algorithm,the stitching body coil image is used to correct the stitching surface coil image.The scheme proposed in this paper maintains the contrast between tissues well while correcting the intensity inhomogeneity in the surface coil image.