High-resolution tomographic imaging by means of x-ray micro-computed tomography (µCT) has been widely utilized for morphological evaluations in dentistry and medicine. The use of µCT follows a standard procedure: image acquisition, reconstruction, processing, evaluation using image analysis, and reporting of results. This paper discusses methods of µCT using a specific scanning device, the Bruker SkyScan 1173 High Energy Micro-CT. We present a description of the general workflow, information on terminology for the measured parameters and corresponding units, and further analyses that can potentially be conducted with this technology. Brief qualitative and quantitative analyses, including basic image processing (VOI selection and thresholding) and measurement of several morphometrical variables (total VOI volume, object volume, percentage of total volume, total VOI surface, object surface, object surface/volume ratio, object surface density, structure thickness, structure separation, total porosity) were conducted on two samples, the mandible of a wistar rat and a urinary tract stone, to illustrate the abilities of this device and its accompanying software package. The results of these analyses for both samples are reported, along with a discussion of the types of analyses that are possible using digital images obtained with a µCT scanning device, paying particular attention to non-diagnostic ex vivo research applications.
Anisotropy of magnetic susceptibility (AMS) has been used in various studies related to interpreting the direction of lava flow, some of which have shown ambiguity with regard to the data generated. In this study, we explored an alternative option to support the aforementioned application, using lava flow type igneous rock samples from the Ijen Volcanic Complex, East Java, Indonesia. We have investigated the preferred rock pore orientations from micro-computed tomography (μCT) images and quantified their directions. We then calculated their correlation with AMS data by calculating the angle between preferred pore orientation. The axis with the smallest gap to the preferred pore orientation of each sample was assumed to imply lava flow direction. Different lava flow direction preferences were obtained from different magnetic ellipsoids. Another important factor for consideration is the relative vertical position of the sampling site within a single lava flow unit. Only one out of five samples (ANY2) show good quantitative conformity between AMS data, preferred pore orientation, and topographical slope, despite these limitations. Our results point to a direction that seems to be correct and coherent on a physical basis. Additional research would likely clarify the issues involved. This encourages us to explore and work further in this field of research.
23 November 2017 in IOP Conference Series: Materials Science and Engineering
Digital imaging of a concrete sample using high resolution tomographic imaging by means of X-Ray Micro Computed Tomography (μ-CT) has been conducted to assess the characteristic of the sample's structure. A standard procedure of image acquisition, reconstruction, image processing of the method using a particular scanning device i.e., the Bruker SkyScan 1173 High Energy Micro-CT are elaborated. A qualitative and a quantitative analysis were briefly performed on the sample to deliver some basic ideas of the capability of the system and the bundled software package. Calculation of total VOI volume, object volume, percent of object volume, total VOI surface, object surface, object surface/volume ratio, object surface density, structure thickness, structure separation, total porosity were conducted and analysed. This paper should serve as a brief description of how the device can produce the preferred image quality as well as the ability of the bundled software packages to help in performing qualitative and quantitative analysis.
The presence of closed pore in porous rock provide various effect with regard to its structural, elastic and flow properties. Physical based approach to measure porosity such as mercury porosimetry injection is unable to locate closed pore inside porous rock even though it is still possible to quantify the closed porosity. Digital data of porous rock in the form of three dimensional image can now be obtained by means of several methods such as micro-CT scan. Using the digital data, closed pore can be identified and isolated using digital rock physics approach. We first construct a synthetic three dimensional porous sample which consist of two simple side-to-side connected pore (cylinder and box shaped) and two spherical isolated pore which has closed porosity of 1.41 %. The digital image analysis which implemented in software CTAn (Bruker Micro-CT) still produce error of 0.04% which is very low. However, analysis using Lattice Boltzmann Method based simulation of fluid flow provide exact match to the closed porosity of the synthetic sample. Nevertheless, there are two disadvantages of this method, i.e., the simulation could take hours compared to the digital image analysis which only took several minutes and the limitation of numerical definition of zero velocity. Thus we apply both methods in order to overcome the drawbacks of each methods to analyze the digital sample of Fontainebleau sandstone. Using CTAn, we obtained the closed porosity of 0.02891845 % and using the LBM based fluid flow simulation of 0.028948346 %. The closed pore can then be isolated to further calculate the surface area. The result also confirmed that pore space of Fontainebleau sandstone is well connected.
Micro Computed Tomography (μCT) has been largely used to perform micrometer scale imaging of specimens, bone biopsies and small animals for the study of porous or cavity-containing objects. One of its favored applications is for assessing structural properties of bone. In this research, we perform a pilot study to visualize and characterize bone structure of a chicken bone thigh, as well as to delineate its cortical and trabecular bone regions. We utilize an In-Vitro μCT scanner Skyscan 1173 to acquire a three dimensional image data of a chicken bone thigh. The thigh was scanned using X-ray voltage of 45 kV and current of 150 μA. The reconstructed images have spatial resolution of 142.50 μm/pixel. Using image processing and analysis e.i segmentation by thresholding the gray values (which represent the pseudo density) and binarizing the images, we were able to visualize each part of the bone, i.e., the cortical and trabecular regions. Total volume of the bone is 4663.63 mm3, and the surface area of the bone is 7913.42 mm2. The volume of the cortical is approximately 1988.62 mm3 which is nearly 42.64% of the total bone volume. This pilot study has confirmed that the μCT is capable of quantifying 3D bone structural properties and defining its regions separately. For further development, these results can be improved for understanding the pathophysiology of bone abnormality, testing the efficacy of pharmaceutical intervention, or estimating bone biomechanical properties.