In situ X-ray tomography measurements of deformation in cellular solids

International audienceno abstrac

Segmentation of cancellous bone from high-resolution computed tomography images: influence on trabecular bone measurements

International audienceThe quantification of cancellous bone network from computed tomography (CT) images requires a segmentation step which is crucial and difficult because of the partial volume effect in CT images. In this paper, we present and evaluate a new approach for segmenting cancellous bone network from high-resolution CT (HRCT) slices. The idea is first to detect a skeleton from the crest lines of the structure and then to thicken it to extract the whole bone structure by satisfying local neighborhood constraints. The segmentation requires the adjustment of relative and not absolute parameters like most methods. We quantified the influence of these parameters on architectural measurements. Results were first validated by using a physical phantom and then examined on a series of 12 HRCT images of human lumbar vertebra of different ages. We demonstrated that the choice of segmentation parameters yielded important variability on architectural measurements (up to 20%), but less variability than a more commonly used approach. This stresses the importance of settle on the segmentation parameters for once, which is possible with the proposed method

Viewing the early stage of metal foam formation by computed tomography using synchrotron radiation

Foamed aluminium alloy containing 7wt.-% of Si is investigated by µm-resolved X-ray computed tomography (CT) using synchrotron radiation. The foam is fabricated employing a Powder metallurgical route. The evolution of foam microstructure is characterized by studying a series of samples representing different stages of foam expansion obtained by interrupting the foaming process for each sample at different foaming times. The computer tomographic reconstruction provides a 3D image of the pore structure as well as the spatial distribution of the blowing agent and of the pores at different foaming stages

Three-dimensional quantitative analysis of polymer foams from synchrotron radiation x-ray microtomography

International audienceWe propose a three-dimensional and high-resolution quantitative image analysis technique for the investigation of the internal microstructure of polymer foams. Microscopy, which is the conventional method of investigation of foams, images only the surface of samples, though, three-dimensional x-ray computed microtomography (μCT) enables the non-destructive imaging of multiple slices of a sample. It is a powerful technique for the examination of porous and multiphase materials. In this paper, we present the application of three-dimensional synchrotron radiation μCT for the characterization of foam samples. After a brief description of the imaging system, we present three-dimensional image-processing tools developed to extract structural parameters quantifying the internal structure of foams. Results of this three-dimensional quantitative image analysis on various types of plasticized poly vinyl chloride foams are presented. This approach provides a tool to study the relationships between the foam microstructures and their physical properties

CT And Mini-CT 2D-Image Analysis for the Quantitation of Vertebral Trabecular Architecture

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Micro-computed tomographic and SEM study of porous bioceramics using an adaptive method based on the mathematical morphological operations

International audienceNumerous clinical studies have demonstrated the influence of the size, number and shape of pores into calcium phosphate ceramics on the process of bone regeneration. The main objective of this study is to determine the microstructure, the morphological characteristics and classes of pores of the prepared hydroxyapatite bioceramic using an adaptive method based on the mathematical morphological operations. The study was carried out using X-ray microtomography and Scanning Electron Microscopy images. The conventional method of openings alone presents limitation of calculation and not sufficient to achieve our objective. The proposed method allowed us to extract local characteristics and calculate precisely the morphological parameters while preserving the original volume of pores. The number and classes of pores with their size, surface of contact of the component and the number of connected pores to each pore were calculated. The method is subjectively and quantitatively evaluated using different computed phantoms and its efficiency is clearly demonstrated through the different reports and measurements generated. The proposed method can have interesting applications in the characterization of porous materials used in the medical field or in other sectors

A method for the automatic characterization of bone architecture in 3D mice microtomographic images

International audienceWe developed an automatic method to characterize mice bone architecture from three-dimensional (3D) microtomographic images. The distal metaphyses of the femur of mice were imaged using 3D synchrotron radiation microtomography at the European Synchrotron Radiation Facility (ID19) with a voxel size of 6.65 μm. Within each reconstructed volume, a region of interest was defined and trabecular and cortical bones were automatically separated. Then, 3D morphologic and topologic model-independent parameters quantifying the 3D bone architecture were computed in both regions. The technique was applied to study the response of the C57BL/6J@Ico strain of mice submitted to a model of bone loss by hind limb unloading produced by tail-suspension

Study by Microtomography of 3D Porosity Networks in Irradiated Beryllium.

Abstract not availableJRC.E-Institute for Transuranium Elements (Karlsruhe