The Distortion Correction Algorithm Research Based On MR-diffusion Tensor Imaging

Diffusion tensor imaging (DTI) proposed in the1990s is a magnetic resonance imaging technique based on the proliferation of human water molecules movement. At present, DTI is the only imaging method of a non-invasive analysis inside the human brain nerve tissue. DTI images, consisted of different direction diffusion weight imaging (DWI), includes not only the scalar information of the white matter tissue, also contains the vector information of the white matter traveling direction (fiber bundle). Through quantitative calculation and fiber tracking we can gain anatomy information of highlighting white matter fiber and orientation information of the direction of describing the white matter fiber. However, in order to obtain accurate white matter fiber anatomy and direction information, before quantitative calculation, we need register each directional DWI image.DTI is different with image registration of the conventional MRI. In the content of registration, the DTI image registration not only includes the motion artifacts caused by the physiological activities, also includes the eddy current effect which is caused by magnetic field inhomogeneity; in the method of registration, DTI can’t directly make use of the methods of conventional MRI registration.Firstly, DTI principle and its data processing method were described in details. And this paper also described the routine registration algorithm for DTI images as well as the current DTI image registration algorithm research progress and summarized the current problems existed in DTI image registration algorithm. On this basis, the paper proposes a new DTI registration algorithm to improve the conventional DTI matching algorithm generated by the local registration confusion.In addition, in the real acquisition of DTI, the head action will cause the relative change of the diffusion gradient direction. Theoretically, we need implement gradient correction after DTI registration. However, DTI gradient correction algorithm does not have a suitable evaluation method. Therefore, this article has designed a DTI Phantom experiment used to evaluate the DTI gradient correction algorithm.Furthermore, in order to highlight the DTI significance in the fields of brain science research, we carried out a DTI preliminary scientific research work on the pathogenesis of bipolar disorder patients, which also was documented here.