LOTUS-inVivo Micro Computed Tomography System for Imaging of Small Animals and Ex-Vivo Biological Samples

X-ray Computed Tomography (CT), e.g. clinical CT scanners, basically provides Linear Attenuation Coefficients (LACs) of objects under study by the means of algorithmic reconstruction of acquired views of attenuated X-ray passing through the samples in different angles around the imaged sample. Micro Computed Tomography (micro-CT) basically works the same as clinical CT. It provides volumetric information representing the inner structure of objects with a resolution in the micron range. LOTUS-inVivo is a micro-CT scanner dedicated to imaging of small animals and ex-vivo biological samples. In the present study the spatial resolution and Low Contrast Detectability (LCD) of LOTUS-inVivo scanner were evaluated using standard phantoms. We aimed to prove the capability of LOTUS-inVivo for small animal and ex-vivo biological samples imaging using the measured image quality parameters, i.e. spatial resolution and low contrast detectability. By the means of analysis of bar and LCD phantom images, the limiting resolution of LOTUS-inVivo micro-CT scanner was measured about 2.7 µm and has been shown that it’s capable of resolving sizes greater than 12.5 µm. Also, we concluded that LOTUS-inVivo is capable of discriminating tissues with 3% differences in contrast relative to the background, for 1 mm bar size. Thus, the provided technical characteristics in this study have made LOTUS-inVivo as a suitable tool for small animal imaging.

Download Full-text

Investigating the Evolution of Fractures in Clay–based Ceramics During Repeated Freeze-Thawing Cycles Using Micro X-Ray Computed Tomography and Image Analysis

10.26434/chemrxiv.13049627 ◽

2020 ◽

Author(s):

Carlo Porfido ◽

Roberto Rizzo ◽

David Healy ◽

Matteo Spagnuolo ◽

Roberto Terzano ◽

...

Keyword(s):

Computed Tomography ◽

Methodological Approach ◽

Fracture Initiation ◽

Micro Ct ◽

Micro Computed Tomography ◽

X Ray ◽

Freeze Thaw ◽

Fracture Length ◽

Grain Distribution ◽

Fracture Damage

<div><div><div><p>This work presents a study on the fracturing behaviour of a quartz tempered clay-based ceramic subjected to damage in freeze-thaw cycles. X-ray micro-computed tomography (micro-CT) provided high-resolution imaging of the ceramic before and during the freeze-thaw treatment, allowing to analyse a fully water-saturated sample using a special thermal stage designed to keep the sample frozen during analyses. Micro-CT 3D renderings showed the internal features of the specimen (i.e., quartz grain distribution), the increment of fracture count and size, and the detachment of ceramic and/or temper fragments from the edges of the sample over the cycles. Selected 2D micrographs, before and after freeze-thawing treatment, were analysed using the MATLAB toolbox FracPaQ. This software provided detailed data on fracture length, intensity, density, orientation and connectivity, and enabled to interpret the process of fracture initiation and propagation inside the material. These results showed that the temper plays a crucial role in ceramic fracturing behaviour under freeze- thawing conditions, as damage propagation is influenced by quartz grain distribution and orientation within the material. The study described in this work, not only offers new insights into the fracture dynamics of freeze-thawed clay-based ceramics, but also presents a new methodological approach to quantitatively measure fracture damage in porous materials.</p></div></div></div>

Download Full-text

SU-GG-J-16: A Physiologically Gated Micro-CT Scanner for Dynamic Small Animal Imaging Based On a Carbon Nanotube X-Ray Source

Medical Physics ◽

10.1118/1.2961573 ◽

2008 ◽

Vol 35 (6Part5) ◽

pp. 2682-2682

Author(s):

G Cao ◽

R Peng ◽

Y Lee ◽

R Rajaram ◽

X Calderon-Colon ◽

...

Keyword(s):

Carbon Nanotube ◽

Small Animal Imaging ◽

Small Animal ◽

Micro Ct ◽

Ct Scanner ◽

X Ray ◽

Animal Imaging

Download Full-text

A Review of Current Challenges and Case Study toward Optimizing Micro-Computed X-Ray Tomography of Carbon Fabric Composites

Materials ◽

10.3390/ma13163606 ◽

2020 ◽

Vol 13 (16) ◽

pp. 3606

Author(s):

Armin Rashidi ◽

Tina Olfatbakhsh ◽

Bryn Crawford ◽

Abbas S. Milani

Keyword(s):

Computed Tomography ◽

Woven Fabric ◽

Fiber Reinforced Polymers ◽

Micro Ct ◽

Micro Computed Tomography ◽

X Ray ◽

Fabric Composites ◽

Low X ◽

Composite Fabrics

X-ray computed tomography provides qualitative and quantitative structural and compositional information for a broad range of materials. Yet, its contribution to the field of advanced composites such as carbon fiber reinforced polymers is still limited by factors such as low imaging contrast, due to scarce X-ray attenuation features. This article, through a review of the state of the art, followed by an example case study on Micro-computed tomography (CT) analysis of low X-ray absorptive dry and prepreg carbon woven fabric composites, aims to highlight and address some challenges as well as best practices on performing scans that can capture key features of the material. In the case study, utilizing an Xradia Micro-CT-400, important aspects such as obtaining sufficient contrast, an examination of thin samples, sample size/resolution issues, and image-based modeling are discussed. The outcome of an optimized workflow in Micro-CT of composite fabrics can assist in further research efforts such as the generation of surface or volume meshes for the numerical modeling of underlying deformation mechanisms during their manufacturing processes.

Download Full-text

Micro-CT study of Middle Ordovician Spumellaria (radiolarians) from western Newfoundland, Canada

Journal of Paleontology ◽

10.1017/jpa.2019.88 ◽

2020 ◽

Vol 94 (3) ◽

pp. 417-435 ◽

Cited By ~ 2

Author(s):

Sarah Kachovich ◽

Jonathan C. Aitchison

Keyword(s):

Computed Tomography ◽

Three Dimensional ◽

Detailed Examination ◽

Micro Ct ◽

Micro Computed Tomography ◽

Lower Paleozoic ◽

X Ray ◽

Middle Ordovician ◽

Radiolarian Assemblage ◽

Taxonomic Groups

AbstractA new, previously undescribed Middle Ordovician (middle Darriwilian: Dw2) radiolarian assemblage has been recovered from the Table Cove Formation at Piccadilly Quarry, western Newfoundland. Constituents of the fauna described herein are both distinctive and exceptionally well preserved. Three-dimensional X-ray micro-computed tomography (μ-CT) is used to make a detailed examination of four key spumellarian specimens. This technology enables visualization of hitherto ambiguous details of the internal morphologies of key lower Paleozoic taxonomic groups, among which a lack of knowledge has impeded resolution of higher taxonomic rankings.

Download Full-text

Micro-CT imaging of rat lung ventilation using continuous image acquisition during xenon gas contrast enhancement

Journal of Applied Physiology ◽

10.1152/japplphysiol.00009.2007 ◽

2007 ◽

Vol 103 (5) ◽

pp. 1848-1856 ◽

Cited By ~ 33

Author(s):

Wilfred W. Lam ◽

David W. Holdsworth ◽

Louise Y. Du ◽

Maria Drangova ◽

David G. McCormack ◽

...

Keyword(s):

Computed Tomography ◽

Rotation Rate ◽

Lung Ventilation ◽

Region Growing ◽

Micro Ct ◽

Ct Scanner ◽

Micro Computed Tomography ◽

Time Resolved ◽

Seeded Region Growing ◽

Enhanced Computed Tomography

We measured ventilation (V̇) in seven anesthetized, mechanically ventilated, supine Wistar rats. Images of the whole lung were continuously acquired using a dynamic, flat-panel volumetric micro-computed tomography (micro-CT) scanner during ventilation with a xenon/oxygen (Xe-O2) gas mixture. Forty time-resolved volumes consisting of eighty 0.45-mm-thick slices (covering the entire lung) were acquired in 40 s, using a gantry rotation rate of one rotation per second. The animals were ventilated at a respiratory rate of 60 breaths/min, matching the gantry rotation rate, and imaged without suspending ventilation. A previously published theoretical model was modified slightly and used to calculate the whole lung ventilation from volumes of interest generated by seeded region growing. Linear regression of calculated whole lung ventilation volumes vs. expected tidal volumes yielded a slope of 1.12 ± 0.11 (slope ± SE) and a y-intercept of −1.56 ± 0.42 ml ( y-intercept ± SE) with 95% confidence intervals of 0.83 to 1.40 and −2.6 to −0.5 ml, respectively. The same model was used to calculate the regional ventilation in axial slices for each animal. Voxels were fit to the model to yield a map of V̇, which displayed an anterior/posterior gravitational gradient of (−3.9 ± 1.8) × 10−6 ml·s−1·cm−1 for slices immediately superior to the diaphragm and (−6.0 ± 2.4) × 10−6 ml·s−1·cm−1 for slices at the midlevel of the heart (mean ± SD). Thus continuous Xe-enhanced computed tomography enables the noninvasive determination of regional V̇ with the temporal and spatial resolution necessary for rats.

Download Full-text

The Application of X-ray Micro Computed Tomography (Micro-CT) of Core Sample for Estimation of Physicochemical Treatment Efficiency

10.2118/176600-ms ◽

2015 ◽

Cited By ~ 5

Author(s):

Maksim Sergeevich Orlov ◽

Pavel Valeriyevich Roschin ◽

Ivan Aleksandrovich Struchkov ◽

Vladimir Tarasovich Litvin

Keyword(s):

Computed Tomography ◽

Core Sample ◽

Micro Ct ◽

Micro Computed Tomography ◽

Treatment Efficiency ◽

Physicochemical Treatment ◽

X Ray

Download Full-text

Diagnostic value of ex-vivo three-dimensional micro-computed tomography imaging of primary nonhematopoietic human bone tumors: osteosarcoma versus chondrosarcoma

Acta Radiologica ◽

10.1080/02841850802247673 ◽

2008 ◽

Vol 49 (8) ◽

pp. 940-948 ◽

Cited By ~ 1

Author(s):

A. C. Langheinrich ◽

C. Stolle ◽

M. Kampschulte ◽

D. Lommel ◽

W. S. Rau ◽

...

Keyword(s):

Computed Tomography ◽

Bone Tumors ◽

Ex Vivo ◽

Quantitative Information ◽

Human Bone ◽

Histopathological Analysis ◽

Micro Ct ◽

Micro Computed Tomography ◽

Delay In Diagnosis ◽

Ct Density

Background: Osteosarcoma and chondrosarcoma are the most common nonhematopoietic primary malignancies of bone. However, unusual radiographic appearances can lead to delay in diagnosis and confusion with benign diseases. Purpose: To evaluate the feasibility of micro-computed tomography (CT) for the analysis of primary, nonhematopoietic human bone tumors ex vivo. Material and Methods: Samples from 12 human bone specimens (osteosarcoma, n=6; chondrosarcoma, n=6) obtained for diagnostic purposes were scanned using industrial X-ray film without amplifier foil and scanned with micro-CT (7- and 12-µm-cubic voxels). Trabecular bone CT “density” and tumor matrix CT “density” were determined, and results were compared with those obtained from a detailed conventional histopathologic analysis of corresponding cross-sections. The significance of differences in grayscale measurements was tested with analysis of variance. Results: Micro-CT provided quantitative information on bone morphology equivalent to histopathological analysis. We established grayscale measurements by which tumor matrices of chondrosarcoma and osteosarcoma could be radiographically categorized following histological classifications ( P<0.001). Conclusion: Micro-CT is feasible for the analysis and differentiation of human osteosarcoma and chondrosarcoma.

Download Full-text

Erbium-Based Perfusion Contrast Agent for Small-Animal Microvessel Imaging

Contrast Media & Molecular Imaging ◽

10.1155/2017/7368384 ◽

2017 ◽

Vol 2017 ◽

pp. 1-10 ◽

Cited By ~ 3

Author(s):

Justin J. Tse ◽

P. Joy Dunmore-Buyze ◽

Maria Drangova ◽

David W. Holdsworth

Keyword(s):

Contrast Agent ◽

Contrast Agents ◽

Spectral Band ◽

Small Animal ◽

Micro Ct ◽

Micro Computed Tomography ◽

Preclinical Research ◽

X Ray ◽

Tissue Specimens ◽

X Ray Absorption

Micro-computed tomography (micro-CT) facilitates the visualization and quantification of contrast-enhanced microvessels within intact tissue specimens, but conventional preclinical vascular contrast agents may be inadequate near dense tissue (such as bone). Typical lead-based contrast agents do not exhibit optimal X-ray absorption properties when used with X-ray tube potentials below 90 kilo-electron volts (keV). We have developed a high-atomic number lanthanide (erbium) contrast agent, with a K-edge at 57.5 keV. This approach optimizes X-ray absorption in the output spectral band of conventional microfocal spot X-ray tubes. Erbium oxide nanoparticles (nominal diameter < 50 nm) suspended in a two-part silicone elastomer produce a perfusable fluid with viscosity of 19.2 mPa-s. Ultrasonic cavitation was used to reduce aggregate sizes to <70 nm. Postmortem intact mice were perfused to investigate the efficacy of contrast agent. The observed vessel contrast was >4000 Hounsfield units, and perfusion of vessels < 10 μm in diameter was demonstrated in kidney glomeruli. The described new contrast agent facilitated the visualization and quantification of vessel density and microarchitecture, even adjacent to dense bone. Erbium’s K-edge makes this contrast agent ideally suited for both single- and dual-energy micro-CT, expanding potential preclinical research applications in models of musculoskeletal, oncological, cardiovascular, and neurovascular diseases.

Download Full-text