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Information-Theoretic Registration with Explicit Reorientation of Diffusion-Weighted Images

By Henrik G. Jensen, François Lauze and Sune Darkner
CSGB Research Reports
No. 05, June 2019

We present an information-theoretic approach to registration of DWI with explicit optimization over the orientational scale, with an additional focus on normalized mutual information as a robust information-theoretic similarity measure for DWI. The framework is an extension of the LOR-DWI density-based hierarchical scale-space model, that varies and optimizes over the integration, spatial, directional, and intensity scales. We extend the model to non-rigid deformations and show that the formulation provides intrinsic regularization through the orientational information. Our experiments illustrate that the proposed model deforms ODFs correctly and is capable of handling the classic complex challenges in DWI-registrations, such as the registration of fiber-crossings along with kissing, fanning and interleaving fibers. Our results clearly illustrate a novel promising regularizing effect, that comes from the nonlinear orientation-based cost function. We illustrate the properties of the different image scales, and show that including orientational information in our model make the model better at retrieving deformations compared to standard scalar-based registration.

Keywords: Registration, Diffusion-Weighted MRI, Normalized Mutual Information, Explicit Reorientation, Analytical Gradients, Density-Based Formulation, Watson Density Function, Free-Form Deformation, Cubic B-Spline.

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