Dissociation of Down syndrome and Alzheimer's disease effects with imaging.

Introduction: Down Syndrome (DS) adults experience accumulation of Alzheimer's disease (AD)-like amyloid plaques and tangles and a high incidence of dementia and could provide an enriched population to study AD-targeted treatments. However, to evaluate effects of therapeutic intervention, it is necessary to dissociate the contributions of DS and AD from overall phenotype. Imaging biomarkers offer the potential to characterize and stratify patients who will worsen clinically but have yielded mixed findings in DS subjects.

Phase unwrapping using an extrapolation-projection algorithm.

We explore an approach to the unwrapping of two-dimensional phase functions using a robust extrapolation-projection algorithm. Phase unwrapping is essential for imaging systems that construct the image from phase information. Unlike some existing methods where unwrapping is performed locally on a pixel-by-pixel basis, this work approaches the unwrapping problem from a global point of view.