Performance of image matching in the computational anatomy gateway: CPU and GPU implementations in opencl

The Computational Anatomy Gateway is a software as a service tool that provides tools for analysis of structural MRI to the neuroimaging community by calculating diffeomorphic mappings between a user's data and well characterized atlas images. These tools include automatic parcellation of brain images into labeled regions, described by dense 3D arrays; and shape analysis of regions described by triangulated sur-faces, for hypothesis testing in specific populations. We have developed mapping techniques that combine the benefits of working with triangulated surfaces with those of working with dense images, and have been working toward uniting these two tools: To automatically perform shape analysis on each segmented subcortical structure simultaneously. In this work we investigate the performance of our algo-rithm across a wide range of input data, examining the effect of number of voxels in 3D images, number of vertices in tri-Angulated surfaces, and number of structures being mapped onto simultaneously. Further, we investigate the performance of our OpenCL code implemented in two different environ-ments: The Intel OpenCL environment on a CPU, and the CUDA OpenCL environment on a GPU. We identify a range of inputs, generally smaller datasets, for which the CPU out performs the GPU. Finally we show the feasibility of mapping onto all the human gray matter sub-cortical structures simultaneously, and discuss our strategy

Sub-Riemannian Methods in Shape Analysis

International audienc

Dysfunctional HDL: from structure-function-relationships to biomarkers

Reduced plasma levels of HDL-C are associated with an increased risk of CAD and myocardial infarction, as shown in various prospective population studies. However, recent clinical trials on lipid-modifying drugs that increase plasma levels of HDL-C have not shown significant clinical benefit. Notably, in some recent clinical studies, there is no clear association of higher HDL-C levels with a reduced risk of cardiovascular events observed in patients with existing CAD. These observations have prompted researchers to shift from a cholesterol-centric view of HDL towards assessing the function and composition of HDL particles. Of importance, experimental and translational studies have further demonstrated various potential antiatherogenic effects of HDL. HDL has been proposed to promote macrophage reverse cholesterol transport and to protect endothelial cell functions by prevention of oxidation of LDL and its adverse endothelial effects. Furthermore, HDL from healthy subjects can directly stimulate endothelial cell production of nitric oxide and exert anti-inflammatory and antiapoptotic effects. Of note, increasing evidence suggests that the vascular effects of HDL can be highly heterogeneous and HDL may lose important anti-atherosclerotic properties and turn dysfunctional in patients with chronic inflammatory disorders. A greater understanding of mechanisms of action of HDL and its altered vascular effects is therefore critical within the context of HDL-targeted therapies