A Chi-Square Type Test for Time-Invariant Fiber Pathways of the Brain

Oregon Convention Center 

A longitudinal diffusion tensor imaging (DTI) study on a single
brain can be remarkably useful to probe white matter fiber connectivity that
may or may not be stable over time. We consider a novel testing problem
where the null hypothesis states that the trajectories of a coherently oriented
fiber population remain the same over a fixed period of time. Compared to
other applications that use changes in DTI scalar metrics over time, our test is
focused on the partial derivative of the continuous ensemble of fiber trajectories
with respect to time. The test statistic is shown to have the limiting chi-square
distribution under the null hypothesis. The power of the test is demonstrated
using Monte Carlo simulations based on both the theoretical and empirical
critical values. The proposed method is applied to a longitudinal DTI study
of a normal brain.

Functional central limit theorem

Nadaraya-Watson type kernel estimator


White matter fiber tractography 

Section on Statistics in Imaging