2012 Winter Project Week: DTI Change Modeling

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  Projects List

Key Partners

• Utah: Anuja Sharma, Guido Gerig
• Iowa: Hans Johnson (HD Project)

Objective

We have developed a new framework for spatiotemporal analysis of parameterized functions attributed by properties of 4D longitudinal image data. Our objective is to apply the framework to model patient-specific changes along white matter tracts using serial DTI data from subjects with Huntington's disease. As an extension, multiple subjects could be modeled and compared for assessment of normative trends.

Approach, Plan

• Co-register all available intra-subject, serial DTI volumes to create a consistent atlas tract geometry (and inter-subject if multiple subjects are to be compared eventually).
• Perform atlas-based tractography followed by back-mapping to assemble scalar diffusion parameters as functions of arc length along tracts of interest.
• Apply our methodology to quantify longitudinal DTI changes along tracts using these arc length parameterized diffusion functions.

Progress

To be added

Registration and Tractography

Tensor derived FA Atlas Slices from the mean atlas FA image computed by registering a couple of HD cases and Controls.

axial slice

coronal slice

sagittal slice

Tractography in atlas space for mid-corpus callosum tract Shown here are the source and target ROI placements along with the resulting fiber bundle representing the middle section of the corpus callosum white matter tract. This tract geometry is then mapped back to individual subjects to assemble subject specific diffusion information along the tract's length. The consistent across-subject tract definition provides a reference frame for comparison.

ROI placement in the atlas space

Mid-corpus callosum tract obtained via tractography.

References

• Casey B. Goodlett, P. Thomas Fletcher, John H. Gilmore, Guido Gerig. Group Analysis of DTI Fiber Tract Statistics with Application to Neurodevelopment. NeuroImage 45 (1) Supp. 1, 2009. p. S133-S142
• Details of the framework