Quantitative analysis for the connectivity of nerve bundles using MR DTI

Diffusion tensor imaging (DTI) has become a powerful tool for analyzing the structure of nerve bundles in white matter. However, there are still problems to investigate the connectivity of the nerve bundles. The main problem is to detect a junction. Solving such problems, we consider a scalar potential field using several characteristics of the diffusion tensor extracted from DTI. The characteristics include fractional anisotropy (FA) itself, the similarity of the principal axis of the diffusion tensor, and FA. This approach is different from a conventional tracking-detecting method as for considering not only the orientation of tissues but also the similarity of characteristics of the neighborhood. To make the scalar potential field, we multiply the magnitude of each characteristic. In such field, we could give the high potential value for the high possibility of nerve bundle existence. Then we propose the method to estimate the connectivity of the nerve bundles between any two points in the field. We also apply the method to clinical data. From the result, we obtain the line integral of the potential between two points on the field that will be treated as the communication pathway of the nerve bundles. The goal is to obtain the qualitative in vivo analysis of the connectivity of nerve bundles and this study is the first step.