Complementing clinical findings with those generated by biomarkers--such as β-amyloid-targeted positron emission tomography (PET) imaging--has been proposed as a means of increasing overall accuracy ...in the diagnosis of Alzheimer's disease (AD). Florbetaben (^sup 18^FBAY 94-9172) is a novel β-amyloid PET tracer currently in global clinical development. We present the results of a proof of mechanism study in which the diagnostic efficacy, pharmacokinetics, safety and tolerability of florbetaben were assessed. The value of various quantitative parameters derived from the PET scans as potential surrogate markers of cognitive decline was also investigated. Ten patients with mild-moderate probable AD (DSM-IV and NINCDS-ADRDA criteria) and ten age-matched (≥ 55 years) healthy controls (HCs) were administered a single dose of 300 MBq florbetaben, which contained a tracer mass dose of<5 μg. The 70-90 min post-injection brain PET data were visually analysed by three blinded experts. Quantitative assessment was also performed via MRI-based, anatomical sampling of predefined volumes of interest (VOI) and subsequent calculation of standardized uptake value (SUV) ratios (SUVRs, cerebellar cortex as reference region). Furthermore, single-case, voxelwise analysis was used to calculate individual "whole brain β-amyloid load". Visual analysis of the PET data revealed nine of the ten AD, but only one of the ten HC brains to be β-amyloid positive (p=0.001), with high inter-reader agreement (weighted kappa≥0.88). When compared to HCs, the neocortical SUVRs were significantly higher in the ADs (with descending order of effect size) in frontal cortex, lateral temporal cortex, occipital cortex, anterior and posterior cingulate cortices, and parietal cortex (p=0.003-0.010). Voxel-based group comparison confirmed these differences. Amongst the PET-derived parameters, the Statistical Parametric Mapping-based whole brain β-amyloid load yielded the closest correlation with the Mini-Mental State Examination scores (r=-0.736, p<0.001), following a nonlinear regression curve. No serious adverse events or other safety concerns were seen. These results indicate florbetaben to be a safe and efficacious β-amyloid-targeted tracer with favourable brain kinetics. Subjects with AD could be easily differentiated from HCs by both visual and quantitative assessment of the PET data. The operator-independent, voxel-based analysis yielded whole brain β-amyloid load which appeared valuable as a surrogate marker of disease severity.PUBLICATION ABSTRACT
This book constitutes the thoroughly refereed joint post-proceedings of nine workshops held as part of the 10th International Conference on Extending Database Technology, EDBT 2006, held in Munich, ...Germany in March 2006. The 70 revised full papers presented were selected from numerous submissions during two rounds of reviewing and revision.
GiST scan acceleration using coprocessors Beier, Felix; Kilias, Torsten; Sattler, Kai-Uwe
Proceedings of the Eighth International Workshop on Data Management on New Hardware,
05/2012
Conference Proceeding
Efficient lookups in huge, possibly multi-dimensional datasets are crucial for the performance of numerous use cases that generate multiple search operations at the same time, like point queries in ...ray tracing or spatial joins in collision detection of interactive 3D applications. These applications greatly benefit from index structures that quickly filter relevant candidates for further processing. Since different lookup operations are independent from each other, they might be processed in parallel on modern hardware like multi-core CPUs or GPUs. But implementing efficient algorithms for all kinds of indexes on various hardware platforms is a challenging task. In this paper, we present a new approach that extends the existing GiST index framework with an abstraction layer for the hardware where index operations are executed. Furthermore, we provide first performance evaluations for the scan execution on CPUs and an Nvidia Tesla GPU.
