Generalized Tensor-Based Morphometry of HIV/AIDS Using Multivariate Statistics on Deformation Tensors
Source: IEEE Transactions on Medical Imaging
2008 Jan;27(1):129-141.
Author: Lepore N, Brun CA, Chou YY, Chiang MC, Dutton RA, Hayashi KM, Luders E, Lopez OL, Aizenstein HJ, Toga AW, Becker JT & Thompson PM
Abstract:
This paper investigates the performance of a new multivariate
method for tensor-based morphometry (TBM). Statistics
on Riemannian manifolds are developed that exploit the full information
in deformation tensor fields. In TBM, multiple brain images
are warped to a common neuroanatomical template via 3-D
nonlinear registration; the resulting deformation fields are analyzed
statistically to identify group differences in anatomy. Rather
than study the Jacobian determinant (volume expansion factor) of
these deformations, as is common, we retain the full deformation
tensors and apply a manifold version of Hotelling’s 2 test to them,
in a Log-Euclidean domain. In 2-D and 3-D magnetic resonance
imaging (MRI) data from 26 HIV/AIDS patients and 14 matched
healthy subjects, we compared multivariate tensor analysis versus
univariate tests of simpler tensor-derived indices: the Jacobian determinant,
the trace, geodesic anisotropy, and eigenvalues of the
deformation tensor, and the angle of rotation of its eigenvectors.
We detected consistent, but more extensive patterns of structural
abnormalities, with multivariate tests on the full tensor manifold.
Their improved power was established by analyzing cumulative
-value plots using false discovery rate (FDR) methods, appropriately
controlling for false positives. This increased detection sensitivity
may empower drug trials and large-scale studies of disease
that use tensor-based morphometry.