Relevant bibliographies by topics / Microstructural imaging

Academic literature on the topic 'Microstructural imaging'

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Published: 1 June 2024

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  1. Journal articles
  2. Dissertations / Theses
  3. Books
  4. Book chapters
  5. Conference papers
  6. Reports

Journal articles on the topic "Microstructural imaging":

1

Alotaibi, Abdulmajeed, Christopher Tench, Rebecca Stevenson, Ghadah Felmban, Amjad Altokhis, Ali Aldhebaib, Rob A. Dineen, and Cris S. Constantinescu. "Investigating Brain Microstructural Alterations in Type 1 and Type 2 Diabetes Using Diffusion Tensor Imaging: A Systematic Review." Brain Sciences 11, no. 2 (January 22, 2021): 140. http://dx.doi.org/10.3390/brainsci11020140.

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Type 1 and type 2 diabetes mellitus have an impact on the microstructural environment and cognitive functions of the brain due to its microvascular/macrovascular complications. Conventional Magnetic Resonance Imaging (MRI) techniques can allow detection of brain volume reduction in people with diabetes. However, conventional MRI is insufficiently sensitive to quantify microstructural changes. Diffusion Tensor Imaging (DTI) has been used as a sensitive MRI-based technique for quantifying and assessing brain microstructural abnormalities in patients with diabetes. This systematic review aims to summarise the original research literature using DTI to quantify microstructural alterations in diabetes and the relation of such changes to cognitive status and metabolic profile. A total of thirty-eight published studies that demonstrate the impact of diabetes mellitus on brain microstructure using DTI are included, and these demonstrate that both type 1 diabetes mellitus and type 2 diabetes mellitus may affect cognitive abilities due to the alterations in brain microstructures.
2

Talmon, Yeshayahu. "Cryo-TEM of amphiphilic polymer and amphiphile/polymer solutions." Proceedings, annual meeting, Electron Microscopy Society of America 51 (August 1, 1993): 876–77. http://dx.doi.org/10.1017/s0424820100150216.

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To achieve complete microstructural characterization of self-aggregating systems, one needs direct images in addition to quantitative information from non-imaging, e.g., scattering or Theological measurements, techniques. Cryo-TEM enables us to image fluid microstructures at better than one nanometer resolution, with minimal specimen preparation artifacts. Direct images are used to determine the “building blocks” of the fluid microstructure; these are used to build reliable physical models with which quantitative information from techniques such as small-angle x-ray or neutron scattering can be analyzed.To prepare vitrified specimens of microstructured fluids, we have developed the Controlled Environment Vitrification System (CEVS), that enables us to prepare samples under controlled temperature and humidity conditions, thus minimizing microstructural rearrangement due to volatile evaporation or temperature changes. The CEVS may be used to trigger on-the-grid processes to induce formation of new phases, or to study intermediate, transient structures during change of phase (“time-resolved cryo-TEM”). Recently we have developed a new CEVS, where temperature and humidity are controlled by continuous flow of a mixture of humidified and dry air streams.
3

Kane, Genevieve A., M. David Frey, and Robert Hull. "Influence of Controlled Cooling Rates During Thermal Processing of Ti 6% Al 4% V Alloys Using In-Situ Scanning Electron Microscopy." MRS Advances 5, no. 29-30 (2020): 1603–11. http://dx.doi.org/10.1557/adv.2020.190.

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ABSTRACTWe describe experimental approaches to real time examination of the microstructural evolution of Ti 6%Al 4%V upon cooling from above the beta transus (~995 °C) while imaging in the scanning electron microscope. Ti 6%Al 4%V is a two phase, α+β titanium alloy with high strength and corrosion resistance. The β →α transformation on cooling can give rise to different microstructures and properties through various thermal treatments. Fully lamellar microstructures, bi-modal microstructures, and equiaxed microstructures can each be obtained by accessing different cooling rates upon the final treatment above the beta temperature, each resulting in uniquely enhanced material properties.Utilizing the capabilities of a heating/ tensile stage developed by Kammrath & Weiss Inc., are able to apply real-time imaging techniques in the scanning electron microscope to monitor the development of the microstructure. Annealing temperatures up to 1100 °C are attainable, with cooling rates ranging from 0.1 ° C per second to 3.3 °C per second. This has allowed us to directly observe the formation of lamellae at different annealing temperature/ cooling rate combinations to determine the lamellar microstructure width, separation, and colony size.
4

Jaganathan, Sudhakar, Hooman V. Tafreshi, and Behnam Pourdeyhimi. "Two-Scale Modeling Approach to Predict Permeability of Fibrous Media." Journal of Engineered Fibers and Fabrics 3, no. 2 (June 2008): 155892500800300. http://dx.doi.org/10.1177/155892500800300208.

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We previously demonstrated how one can develop a 3–D geometry to model the fibrous microstructure of a nonwoven fiberweb and use it to simulate its permeability at fiber level [1–6]. Developing 3–D models of most nonwoven fabrics (bonded fiberwebs), however, is cumbersome, as in the case of hydroentangled fabrics, for instance. In such cases, microscopic techniques are often used to generate 3–D images of the media's microstructures. Nevertheless, whether the microstructure is modeled or obtained from 3–D imaging, extensive computational resources are required to use them in fluid flow simulations [7]. To circumvent this problem, a two-scale modeling approach is proposed here that allows us to simulate the entire thickness of a commercial fabric/filter on a personal computer. In particular, the microscale permeability of a hydroentangled nonwoven is computed using 3–D reconstructed microstructures obtained from Digital Volumetric Imaging (DVI). The resulting microstructural permeability tensors are then used in a macroscale porous model to simulate the flow through the material's thickness and the calculation of its overall permeability.
5

Vander Voort, George Frederic, Beatriz Suárez-Peña, and Juan Asensio-Lozano. "Metallographic Assessment of Al-12Si High-Pressure Die Casting Escalator Steps." Microscopy and Microanalysis 20, no. 5 (July 7, 2014): 1486–93. http://dx.doi.org/10.1017/s143192761400172x.

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AbstractA microstructural characterization study was performed on high-pressure die cast specimens extracted from escalator steps manufactured from an Al-12 wt.% Si alloy designed for structural applications. Black and white, color light optical imaging and scanning electron microscopy techniques were used to conduct the microstructural analysis. Most regions in the samples studied contained globular-rosette primary α-Al grains surrounded by an Al-Si eutectic aggregate, while primary dendritic α-Al grains were present in the surface layer. This dendritic microstructure was observed in the regions where the melt did not impinge directly on the die surface during cavity filling. Consequently, microstructures in the surface layer were nonuniform. Utilizing physical metallurgy principles, these results were analyzed in terms of the applied pressure and filling velocity during high-pressure die casting. The effects of these parameters on solidification at different locations of the casting are discussed.
6

Li, Kexue, Junliang Liu, Chris R. M. Grovenor, and Katie L. Moore. "NanoSIMS Imaging and Analysis in Materials Science." Annual Review of Analytical Chemistry 13, no. 1 (June 12, 2020): 273–92. http://dx.doi.org/10.1146/annurev-anchem-092019-032524.

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High-resolution SIMS analysis can be used to explore a wide range of problems in material science and engineering materials, especially when chemical imaging with good spatial resolution (50–100 nm) can be combined with efficient detection of light elements and precise separation of isotopes and isobaric species. Here, applications of the NanoSIMS instrument in the analysis of inorganic materials are reviewed, focusing on areas of current interest in the development of new materials and degradation mechanisms under service conditions. We have chosen examples illustrating NanoSIMS analysis of grain boundary segregation, chemical processes in cracking, and corrosion of nuclear components. An area where NanoSIMS analysis shows potential is in the localization of light elements, in particular, hydrogen and deuterium. Hydrogen embrittlement is a serious problem for industries where safety is critical, including aerospace, nuclear, and oil/gas, so it is imperative to know where in the microstructure hydrogen is located. By charging the metal with deuterium, to avoid uncertainty in the origin of the hydrogen, the microstructural features that can trap hydrogenic species, such as precipitates and grain and phase boundaries, can be determined by NanoSIMS analysis on a microstructurally relevant scale.
7

Leyssens, Lisa, Camille Pestiaux, and Greet Kerckhofs. "A Review of Ex Vivo X-ray Microfocus Computed Tomography-Based Characterization of the Cardiovascular System." International Journal of Molecular Sciences 22, no. 6 (March 23, 2021): 3263. http://dx.doi.org/10.3390/ijms22063263.

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Cardiovascular malformations and diseases are common but complex and often not yet fully understood. To better understand the effects of structural and microstructural changes of the heart and the vasculature on their proper functioning, a detailed characterization of the microstructure is crucial. In vivo imaging approaches are noninvasive and allow visualizing the heart and the vasculature in 3D. However, their spatial image resolution is often too limited for microstructural analyses, and hence, ex vivo imaging is preferred for this purpose. Ex vivo X-ray microfocus computed tomography (microCT) is a rapidly emerging high-resolution 3D structural imaging technique often used for the assessment of calcified tissues. Contrast-enhanced microCT (CE-CT) or phase-contrast microCT (PC-CT) improve this technique by additionally allowing the distinction of different low X-ray-absorbing soft tissues. In this review, we present the strengths of ex vivo microCT, CE-CT and PC-CT for quantitative 3D imaging of the structure and/or microstructure of the heart, the vasculature and their substructures in healthy and diseased state. We also discuss their current limitations, mainly with regard to the contrasting methods and the tissue preparation.
8

Sheng, Wei, Weipeng Li, Ji Qi, Teng Liu, Honghui He, Yang Dong, Shaoxiong Liu, Jian Wu, Daniel Elson, and Hui Ma. "Quantitative Analysis of 4 × 4 Mueller Matrix Transformation Parameters for Biomedical Imaging." Photonics 6, no. 1 (March 26, 2019): 34. http://dx.doi.org/10.3390/photonics6010034.

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Mueller matrix polarimetry is a potentially powerful technique for obtaining microstructural information of biomedical specimens. Thus, it has found increasing application in both backscattering imaging of bulk tissue samples and transmission microscopic imaging of thin tissue slices. Recently, we proposed a technique to transform the 4 × 4 Mueller matrix elements into a group of parameters, which have explicit associations with specific microstructural features of samples. In this paper, we thoroughly analyze the relationships between the Mueller matrix transformation parameters and the characteristic microstructures of tissues by using experimental phantoms and Monte Carlo simulations based on different tissue mimicking models. We also adopt quantitative evaluation indicators to compare the Mueller matrix transformation parameters with the Mueller matrix polar decomposition parameters. The preliminary imaging results of bulk porcine colon tissues and thin human pathological tissue slices demonstrate the potential of Mueller matrix transformation parameters as biomedical diagnostic indicators. Also, this study provides quantitative criteria for parameter selection in biomedical Mueller matrix imaging.
9

Alvis, Roger, David Dingley, and David Field. "Observation of grain superstructure in thin aluminum films by orientation imaging microscopy." Proceedings, annual meeting, Electron Microscopy Society of America 53 (August 13, 1995): 436–37. http://dx.doi.org/10.1017/s0424820100138555.

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The correlation of aluminum alloy reliability data to microstructure has long been the goal of those scientists seeking to model electromigration behavior of interconnects. Traditionally, microstructural information has been acquired through x-ray diffraction , and transmission electron microscopy (TEM). However, each of these techniques is capable of delivering only part of the characterization whole. We describe the application of orientation imaging microscopy (OIM) to thin aluminum alloy films and demonstrate its versatility in providing the key microstructural reliability parameters: namely texture and grain size, as well as providing insight to the microstructure of grain boundaries.OIM was performed on an electromigration test structure (figure 1). The Al-alloy was deposited on titanium and capped with an anti-reflective titanium nitride. Subsequently, the test structure was patterned and capped with a multilayer blanket consisting of silicon nitride (SiN), and SiO2. The structure was annealed after the SOG deposition at 450° C for 90 minutes, seeing no electrical stressing. The die was removed from the package and deprocessed before the OIM was acquired.
10

Morris, Jonathan C. "Imaging microstructural contact damage in silicon." Proceedings, annual meeting, Electron Microscopy Society of America 51 (August 1, 1993): 1144–45. http://dx.doi.org/10.1017/s0424820100151556.

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The indentation of single crystal silicon has been shown to produce a metal to semiconducting structural phase transformation. This phase transformation dominates the effect of contact damage from both indentation and scratching at low loads and hence affects the results of related mechanical tests. We are examining the microstructure of contact damage in silicon in order to understand better the mechanisms which control its low-load mechanical and tribological behavior. Extensive transmission electron microscopy (TEM) as well as scanning electron microscopy (SEM) have been used to characterize both morphological and structural changes brought about by contact damage.The plan-view bright field image in Figure 1 exhibits strong crystallographic contrast outside of the indented area. The indented area as well as the extrusions emanating from it are amorphous as evidenced by their lack of crystallographic contrast regardless of tilt as well as their diffuse illumination in dark field. Small bits of fragmented polycrystalline silicon are visible at the indentation borders as well as at the tip of one extrusion.
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Journal articles Dissertations / Theses Books

Dissertations / Theses on the topic "Microstructural imaging":

1

Zacharia, Nicole S. B. Massachusetts Institute of Technology. "Thermal imaging of quenched microstructural evolution in steel alloys." Thesis, Massachusetts Institute of Technology, 2001. http://hdl.handle.net/1721.1/118566.

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Thesis: S.B., Massachusetts Institute of Technology, Department of Materials Science and Engineering, 2001.
Cataloged from PDF version of thesis.
Includes bibliographical references (page 41).
A method was devised for quenching undercooled samples of Fe-12Cr-16Ni. The samples were levitated in a magnetic field as a way of containerless processing. They were dropped onto a nucleation trigger and then into a quenching bath. This process was successful in producing quenched samples , but the layer of In-Ga wetting their surface showed problematic in the analysis of the samples. Data shows that double recalescence was observed in a few cases. SEM proved inconclusive and was not sensitive enough to detect the small chemical variations expected in the dendrites. Also, across the entirety of the sample there was no significant partitioning of Cr or Ni.
by Nicole Zacharia.
S.B.
2

Fukutomi, Hikaru. "Neurite imaging reveals microstructural variations in human cerebral cortical gray matter." Kyoto University, 2020. http://hdl.handle.net/2433/253174.

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3

Horne, Nikki Renee. "Microstructural white matter changes in Alzheimer's disease a diffusion tensor imaging study /." Diss., Connect to a 24 p. preview or request complete full text in PDF format. Access restricted to UC campuses, 2008. http://wwwlib.umi.com/cr/ucsd/fullcit?p3296903.

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Thesis (Ph. D.)--University of California, San Diego and San Diego State University, 2008.
Title from first page of PDF file (viewed April 7, 2008). Available via ProQuest Digital Dissertations. Vita. Includes bibliographical references (p. 127-149).
4

Nguyen, Thanh Tung. "Modeling of complex microcracking in cement based materials by combining numerical simulations based on a phase-field method and experimental 3D imaging." Thesis, Paris Est, 2015. http://www.theses.fr/2015PESC1152/document.

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Une approche combinant simulation numérique et expérimentation est développée pour modéliser la microfissuration complexe dans des matériaux hétérogènes cimentaires. Le modèle numérique proposé a permis de prévoir précisément en 3D l'initiation et la propagation des microfissures à l'échelle de la microstructure réelle d'un échantillon soumis à un chargement de compression. Ses prévisions ont été validées par une comparaison directe avec le réseau de fissures réel caractérisé par des techniques d'imagerie 3D. Dans une première partie, nous développons et testons les outils de simulation numérique. Plus précisément, la méthode de champ de phase est appliquée pour simuler la microfissuration dans des milieux fortement hétérogènes et ses avantages pour ce type de modélisation sont discutés. Ensuite, une extension de cette méthode est proposée pour tenir compte d'un endommagement interfacial, notamment aux interfaces inclusion/matrice. Dans une deuxième partie, les méthodes expérimentales utilisées et développées au cours de cette thèse sont décrites. Les procédures utilisées pour obtenir l'évolution du réseau de fissures 3D dans les échantillons à l'aide de microtomographie aux rayons X et d'essais mécaniques in-situ sont présentées. Ensuite, les outils de traitement d'image utilisant la corrélation d'images volumiques, pour extraire les fissures des images en niveaux de gris avec une bonne précision, sont détaillés. Dans une troisième partie, les prévisions du modèle numérique sons comparées avec les données expérimentales d'un matériau modèle en billes de polystyrène expansé intégrées dans une matrice de plâtre dans un premier temps, et, dans un second temps, d'un béton léger plus complexe. Plus précisément, nous utilisons les données expérimentales pour identifier les paramètres microscopiques inconnus par une approche inverse, et utilisons les déplacements expérimentaux déterminés par corrélation d'images volumiques pour définir des conditions limites à appliquer sur les bords de sous-domaines dans l'échantillon pour les simulations. Les comparaisons directes de réseaux de microfissures 3D et de leur évolution montrent une très bonne capacité prédictive du modèle numérique
An approach combining numerical simulations and experimental techniques is developed to model complex microcracking in heterogeneous cementitious materials. The proposed numerical model allowed us to predict accurately in 3D the initiation and the propagation of microcracks at the scale of the actual microstructure of a real sample subjected to compression. Its predictions have been validated by a direct comparison with the actual crack network characterized by 3D imaging techniques. In a first part, the numerical simulation tools are developed and tested. More specifically, the phase-field method is applied to microcracking simulations in highly heterogeneous microstructures and its advantages for such simulations are discussed. Then, the technique is extended to account for interfacial cracking, possibly occurring at inclusion/matrix interfaces. In a second part, the experimental methods used and developed in this work are described. The procedures to obtain the evolution of the 3D crack network within the samples by means of X-rays computed microtomography and in-situ mechanical testing are presented. Then, we focus on the developed image processing tools based on digital volume correlation to extract with good accuracy the cracks from the grey level images. In a third part, we compare the predictions of the numerical model with experimental results obtained, first, with a model material made of expanded polystyrene beads embedded in a plaster matrix, and second, to a more complex lightweight concrete. More precisely, we use the experimental data to identify by inverse approaches the local microstructural parameters, and use the experimental displacements measured by digital volume correlation to define boundary conditions to be applied on sub-domains within the sample for the simulations. The obtained direct comparisons of 3D microcrack networks and their evolutions demonstrate the very good predictive capability of the numerical model
5

Gong, Nanjie, and 龔南杰. "Probing tissue microstructural changes in neurodegenerative processes using non-gaussian diffusion MR imaging." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2014. http://hdl.handle.net/10722/208583.

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Development of non-invasive imaging biomarkers sensitive to microstructural organization is crucial for deepening our understanding of mechanisms underlying neurodegenerative processes such as aging and further improving early diagnosis and monitoring of neurodegenerative disease such as Alzheimer’s disease (AD) and amnestic mild cognitive impairment (MCI). The diffusional kurtosis imaging (DKI) is an extension of conventional diffusion tensor imaging. It is hypothesized that DKI will provide complementary information to conventional diffusivity metrics in a new dimension that will more comprehensively capture microstructural changes in anisotropic white matter tracts and particularly in relatively isotropic tissues such as gray matter during neurodegenerative processing of aging, MCI and AD and probably improve the early diagnosis of the diseases. Firstly, DKI method and a white-matter model that provided metrics of explicit neurobiological interpretations were applied on healthy participants. In white matter tracts, age-related degenerations appeared to be broadly driven by axonal loss. Demyelination may also be a major driving mechanism, although confined to the anterior brain. In terms of deep gray matter, higher mean kurtosis (MK) and fractional anisotropy (FA) in the globus pallidus, substantia nigra, and red nucleus reflected higher microstructural complexity and directionality compared with the putamen, caudate nucleus, and thalamus. In particular, unique age-related positive correlations for FA, MK, and radial kurtosis (KR) in the putamen opposite to those in other regions were observed. Secondly, to verify the speculation that iron deposition could be one probable underlying mechanism driving changes in microstructure, another advance MRI technique of quantitative susceptibility mapping (QSM) was also used in healthy participants. Significant age-related increases of iron were observed in the putamen, red nucleus, substantia nigra, and caudate nucleus. Putamen exhibited the highest rate of iron accumulation with aging, which was nearly twice of the rates in substantia nigra and caudate nucleus. Significant positive correlations between susceptibility value and diffusion measurements were observed for FA and MK in the putamen as well as FA in the red nucleus. Thirdly, whether DKI metrics could serve as imaging biomarkers to indicate the severity of cognitive deficiency for AD and MCI was investigated. In AD, significantly increased diffusivity and decreased kurtosis parameters were observed in both white and gray matter of the parietal and occipital lobes as compared to MCI. Significantly decreased FA was also observed in the white matter of these lobes in AD. With the exception of FA and KR, all the other five DKI metrics exhibited significant correlations with mini-mental state examination score in both white and gray matter. Lastly, DKI metrics were compared against volumetry for diagnosis of AD and MCI. In AD vs. aMCI, although no significant difference of either FA or MD was observed in white matter tracts, it is encouraging to note that MK captured loss of microstructural complexity in the superior longitudinal fasciculus and internal capsule. MK in the putamen showed the highest power that outperformed volume of the hippocampus for discriminating AD from normal. Besides, FA in the putamen showed the second highest power for discriminating aMCI from normal.
published_or_final_version
Diagnostic Radiology
Doctoral
Doctor of Philosophy
6

Qian, Wenshu, and 錢文樞. "Detecting microstructural changes in MRI normal-appearing tissues of the central nervous system by diffusion tensor and kurtosis imaging." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2013. http://hdl.handle.net/10722/193462.

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This thesis aimed to investigate the feasibility of two diffusion imaging techniques, Diffusion Tensor Imaging (DTI) and Diffusion Kurtosis Imaging (DKI), on detecting subtle physiological or pathological microstructural changes in normal-appearing neural tissues of human central nervous system. 　　　At first, ten patients with neuromyelitis optica (NMO) and twelve age- and gender-matched healthy subjects were recruited. DTI-derived indices including fractional anisotropy (FA), mean diffusivity (MD), axial and radial diffusivities were quantified in the lateral and dorsal columns of cervical spinal cord. Based on the regions of interest (ROIs) measurement, NMO patients showed reduced FA, increased MD and radial diffusivity compared to control subjects, while axial diffusivity did not show any significant difference. The three former DTI metrics also showed significant correlations with disability scores, and especially FA was found to be sensitive to mild NMO. Our results show that DTI-derived indices can quantitatively assess the white matter (WM) abnormalities with seemingly normal appearance in conventional MRI, and are associated with the level of clinical disability, suggesting that DTI may have great potential as a useful diagnostic tool in the clinical setting. 　　　DKI is an extension of conventional DTI to probe the non-Gaussian diffusion property in biological tissues. Besides the four conventional DTI-derived metrics, DKI also provide three additional kurtosis metrics (mean kurtosis (MK), axial and radial kurtosis). In the second study, ROI-based analysis was used to characterize age-related microstructural changes in WM, cortical and subcortical gray matter (GM) of 27 healthy adults (21~59 yrs). Though the volumes of GM and WM were still preserved, DTI-derived metrics can detect the subtle changes in WM and GM. Meanwhile, MK and radial kurtosis significantly increased in both caudate nucleus and putamen while Thalamus showed little aging effect in the diffusivity and kurtosis metrics but significantly decreased only in FA. Our results demonstrated that DKI is sensitive to detect the age-related alterations in neural microstructures at the stage of early aging. 　　　In addition, DKI has been applied to detect the pathological changes in the normal-appearing neural tissues of 18 patients with multiple sclerosis (MS), compared to 22 healthy controls. Diffuse WM abnormalities have been observed extensively in the brain, revealed by DKI-derived metrics. Though the volumetric and voxel-wise analysis revealed no significant changes in the volume of cortical GM, decreased FA and kurtoses with increased diffusivities in MS group were sensitive to disclose the subtle alterations in global and regional cortical GM tissues. Significant correlations have been found between FA in the global, frontal and temporal cortical GM in relapsing-remitting MS patients and their disability scores, suggesting FA as an important biomarker to monitor the disease progress in cortical GM. Moreover, elevated kurtosis indices in MS patients did not correlate with diffusivities in caudate nucleus, putamen and thalamus, suggesting these metrics may be vulnerable to different pathologic aspects of the disease. 　　　In conclusion, DKI is sensitive to neural alterations during normal aging and in MS pathologies, and can provide complementary information to conventional MRI and DTI.
published_or_final_version
Diagnostic Radiology
Doctoral
Doctor of Philosophy
7

Hillman, Timothy R. "Microstructural information beyond the resolution limit : studies in two coherent, wide-field biomedical imaging systems." University of Western Australia. School of Electrical, Electronic and Computer Engineering, 2008. http://theses.library.uwa.edu.au/adt-WU2008.0085.

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8

Radlinska, Barbara. "«In vivo» imaging of microstructural and molecular neuroplasticity of fibre tracts in human subcortical stroke." Thesis, McGill University, 2013. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=119394.

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Background Studies in acute and chronic post-stroke recovery suggest that both microstructural and molecular changes in stroke-affected fibre tracts are associated with clinical outcome. These processes can be measured noninvasily in the living human brain using Diffusion Tensor Imaging (DTI) and Positron Emission Tomography (PET), and together these neuroimaging techniques provide a detailed multimodal approach to the assessment of post-stroke neuroplasticity. With four controlled prospective studies, this thesis addresses direct and indirect microstructural and neuroinflammatory changes as they progress over time along infarct-affected fibres following subcortical ischaemic stroke of the Pyramidal tract (PT). Methods Patients with subcortical ischaemic stroke either affecting the PT (PT-group) or not (NonPT-group), as well as matched controls with Transient Ischaemic Attack (TIA), underwent both DTI and 11C-[R]-PK11195 PET at 3 weeks and 6 months post-stroke. From the DTI data, the PT (directly affected by the stroke), Callosal Motor Fibres (CMF; indirectly affected by the stroke) and Callosal Occipital Fibres (COF; not affected by stroke) were delineated using deterministic tractography. Fractional Anisotropy (FA) ratios (affected/unaffected hemisphere) were calculated for each tract. FA ratios (rFAPT; rFACMF; rFACOF) were compared within and between groups at both time-points, as well as anterograde and retrograde to the infarct. These ratios were then correlated with clinical outcome measures. From PET data, tracer uptake ratios (URs, affected/unaffected hemisphere) were determined for a set of standardised volumes of interest (VOIs) along the PT. These molecular markers of neuroinflammation were correlated with fibre tract integrity anterograde and retrograde to the infarct and with clinical outcome measures. Results DTI data analyses revealed that mean rFAPT in the PT-group was significantly lower than both NonPT and TIA groups initially and at follow-up, and correlated significantly with clinical outcome measures. PT-group rFACMF decreased over time. At follow-up, PT-group rFACMF was significantly lower than NonPT-group rFACMF and PT-group rFACOF. PT-group rFACMF at follow-up correlated with rFAPT retrograde to the infarct. PET data analyses revealed that PT-group uptake ratios were significantly increased at the level of the infarct and anterograde initially, but only anterograde to the infarct at follow-up. Anterograde uptake ratios were correlated with anterograde rFAPT at the initial time-point, whilst uptake ratios in the infarct were correlated with anterograde rFAPT only at follow-up. After controlling for PT damage, initial brainstem uptake ratios showed a positive correlation with clinical outcome, whereas follow-up uptake ratios in the infarct tended to be negatively correlated. Conclusions Overall, significant progressive changes in both microstructural and molecular neuroimaging parameters can be seen along fibres that have been either directly or indirectly affected by subcortical ischaemic stroke. Changes in fibre integrity, as modelled with DTI, are apparent both anterograde and retrograde to the ischaemic lesion, challenging the notion that decreased FA reflects Wallerian degeneration. This is underscored by the fact that decreases in FA are also apparent in regions with only indirect connections to the infarct. Molecular markers of neuroinflammation are present only in the area of the lesion itself and anterograde to the infarct and are therefore more likely to be associated with Wallerian degeneration. Taken together, DTI and PET provide a clinically meaningful assessment of neuroplasticity in the acute and chronic post-stroke phases.
Contexte Les recherches dans le domaine de la récupération suite à un accident vasculaire cérébral (AVC) suggèrent que les changements morphologiques comme moléculaires sont associés à des résultats cliniques. Ces changements peuvent être mesurés de façon non invasive chez l'être humain grâce à l'utilisation de l'Imagerie par Tenseur de Diffusion (ITD) et de la Tomographique par Émission de Positrons (TEP). Au travers de quatre études prospectives contrôlées, cette thèse s'attache à décrire les changements microstructuraux et neuroinflammatoires au cours de leur progression le long des fibres du Faisceau Pyramidal (FP) affectées par un AVC sous-cortical ischémique. Méthodes Des patients présentant un AVC ischémique sous-cortical, qu'il affecte le Faisceau Pyramidal (groupe FP) ou non (groupe NonFP), ainsi que des participants contrôles ayant présenté un Accident Ischémique Transitoire (AIT) se sont vu proposer des examens de ITD et TEP11C-[R]-PK11195 3 semaines et 6 mois après leur AVC. Concernant les données issues de l'examen par ITD, le FP (affecté directement par l'AVC), les Fibres Calleuses Motrices (FCM; affectées indirectement par l'AVC) et les Fibres Calleuses Occipitales (FCO; non affectées par l'AVC) furent délimitées grâce à l'utilisation de la tractographie. Les ratios (l'hémisphère affecté/non affecté) déterminés par l'Anisotropie Fractionnelle (AF) furent calculés. Ces ratios (rAFFP;rAFFCM; rAFFCO) furent comparés à 3 semaines puis 6 mois post-AVC et également analysés selon leur orientation (antérograde ou rétrograde) par rapport à la lésion, et mis en relation avec des résultats cliniques. Concernant les données issues de l'examen de TEP, le ratio d'absorption de la dose traceuse fut déterminé pour un ensemble de zones d'intérêt standardisées le long du FP. Ces marqueurs moléculaires de neuroinflammation furent mis en relation avec l'intégrité des faisceaux, ainsi qu'avec des résultats cliniques. Résultats Les analyses de l'ITD ont révélé que le ratio moyen rAFFP dans le groupe FP était significativement moins élevé que pour les groupes NonFP comme AIT, à 3 semaines et à 6 mois de l'AVC, et que cela était corrélé à des résultats cliniques. Le ratio rAFFCM du groupe FP a décru avec le temps. 6 mois post AVC, le ratio rAFFCM du groupe FP était significativement moins élevé que celui du groupe NonFP comme celui rAFFCO du groupe FP. Le ratio rAFFCM du groupe FP à 6 mois était corrélé à celui rAFFP rétrograde de la zone lésée. Les analyses des données issues de l'examen de TEP ont révélé que les ratios d'absorption du traceurétaient significativement plus élevés au niveau de la zone lésée et dans le sens antérograde 3 semaines post-AVC pour le groupe FP, mais uniquement dans le sens antérograde à la lésion 6 mois post-AVC. Les ratios dans le sens antérograde étaient corrélés avec le ratio rAFFP antérograde 3 semaines post-AVC, alors que les ratios dans la lésion étaient corrélés avec le ratio antérograde rAFFP seulement 6 mois post-AVC. Après avoir contrôlé la présence de dommages sur le faisceau pyramidal, les ratios initiaux d'absorption au niveau du tronc cérébral présentèrent une corrélation positive avec les résultats cliniques, bien que les ratios au niveau de la lésion tendaient à être négativement corrélés. Conclusions Dans l'ensemble, des changements significatifs concernant les fibres affectées directement ou indirectement par un AVC sous-cortical ischémique peuvent être observés au niveau morphologique comme moléculaire grâce à la neuroimagerie. Des changements dans l'intégrité de la fibre, comme démontrés par l'ITD, sont mis en évidence dans les directions antrérograde comme rétrograde à la zone cérébrale lésée, contestant ainsi la notion qu'une faible Anisotropie Fractionnelle reflète une dégénération Wallérienne. Les marqueurs moléculaires de neuroinflammation sont présents uniquement dans la zone lésée elle-même, et dans les fibres antérogrades.
9

Gongvatana, Assawin. "Microstructural white matter integrity in HIV-infected individuals in the HAART era a diffusion tensor imaging study /." Diss., Connect to a 24 p. preview or request complete full text in PDF format. Access restricted to UC campuses, 2008. http://wwwlib.umi.com/cr/ucsd/fullcit?p3316192.

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Abstract:
Thesis (Ph. D.)--University of California, San Diego and San Diego State University, 2008.
Title from first page of PDF file (viewed September 4, 2008). Available via ProQuest Digital Dissertations. Vita. Includes bibliographical references (p. 81-94).
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Chappell, Michael Hastings. "Developments in the use of diffusion tensor imaging data to investigate brain structure and connectivity." Thesis, University of Canterbury. Physics and Astronomy, 2007. http://hdl.handle.net/10092/1476.

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Diffusion tensor imaging (DTI) is a specialist MRI modality that can identify microstructural changes or abnormalities in the brain. It can also be used to show fibre tract pathways. Both of these features were used in this thesis. Firstly, standard imaging analysis techniques were used to study the effects of mild, repetitive closed head injury on a group of professional boxers. Such data is extremely rare, so the findings of regions of brain abnormalities in the boxers are important, adding to the body of knowledge about more severe traumatic brain injury. The author developed a novel multivariate analysis technique which was used on the same data. This new technique proved to be more sensitive than the standard univariate methods commonly used. An important part of diagnosing and monitoring brain damage involves the use of biomarkers. A novel investigation of whether diffusion parameters obtained from DTI data could serve as bio-markers of cognitive impairment in Parkinson's disease was conducted. This also involved developing a multivariate approach, which displayed increased sensitivity compared with any of the component parameters used singly, and suggested these diffusion measures could be robust bio-markers of cognitive impairment. Fibre tract connectivity between regions of the brain is also a potentially valuable measure for diagnosis and monitoring brain integrity. The feasibility of this was investigated in a multi-modal MRI study. Functional MRI (fMRI) identifies regions of activation associated with a particular task. DTI can then find the pathway of the fibre bundles connecting these regions. The feasibility of using regional connectivity to interrogate brain integrity was investigated using a single healthy volunteer. Fibre pathways between regions activated and deactivated by a working memory paradigm were determined. Though the results are only preliminary, they suggest that this line of research should be continued.
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Books on the topic "Microstructural imaging":

1

Singh, M. Microstructural characterization of reaction-formed silicon carbide ceramics. [Washington, D.C: National Aeronautics and Space Administration, 1995.

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A, Leonhardt T., and United States. National Aeronautics and Space Administration., eds. Microstructural characterization of reaction-formed silicon carbide ceramics. [Washington, D.C: National Aeronautics and Space Administration, 1995.

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Generazio, Edward R. Imaging subtle microstructural variations in ceramics with precision ultrasonic velocity and attenuation measurements. Cleveland, Ohio: National Aeronautics and Space Administration, Lewis Research Center, 1987.

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Ammari, Habib, and Hyeonbae Kang, eds. Imaging Microstructures. Providence, Rhode Island: American Mathematical Society, 2009. http://dx.doi.org/10.1090/conm/494.

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J, Roth Don, and Lewis Research Center, eds. Scaling up the single transducer thickness-independent ultrasonic imaging method for accurate characterization of microstructural gradients in monolithic and composite tubular structures. [Cleveland, Ohio]: National Aeronautics and Space Administration, Lewis Research Center, 1998.

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Workshop on Imaging Microstructures: Mathematical and Computational Challenges (2008 Institut Henri Poincaré). Imaging microstructures: Mathematical and computational challenges : Workshop on Imaging Microstructures, Mathematical and Computational Challenges, June 18-20, 2008, Institute Henri Poincaré, Paris. Edited by Ammari Habib and Kang Hyeonbae. Providence, R.I: American Mathematical Society, 2009.

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Adam, Kruk. Tomografia elektronowa i jej zastosowanie w obrazowaniu i metrologii mikrostruktury materiałów: Electron tomography and its application in imaging and metrology of the microstructure of materials. Kraków: Wydawnictwa AGH, 2012.

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J, Roth Don, and United States. National Aeronautics and Space Administration., eds. Recent advances in nondestructive evaluation made possible by novel uses of video systems. [Washington, D.C.]: NASA, 1990.

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United States. National Aeronautics and Space Administration., ed. Single transducer ultrasonic imaging method that eliminates the effect of plate thickness variation in the image. [Washington, DC]: National Aeronautics and Space Administration, 1996.

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United States. National Aeronautics and Space Administration., ed. X-ray transmission microscope development: Final report; NASA contract NAS8-40185; period of performance, 02/28/95-08/31/97. Huntsville, AL: Center for Microgravity and Materials Research, University of Alabama in Huntsville, 1997.

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Book chapters on the topic "Microstructural imaging":

1

Seydoux-Guillaume, Anne-Magali, Bernard Bingen, Valérie Bosse, Emilie Janots, and Antonin T. Laurent. "Transmission Electron Microscope Imaging Sharpens Geochronological Interpretation of Zircon and Monazite." In Microstructural Geochronology, 261–75. Hoboken, NJ, USA: John Wiley & Sons, Inc., 2017. http://dx.doi.org/10.1002/9781119227250.ch12.

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Kepe, Vladimir, Sung-Cheng Huang, Gary W. Small, Nagichettiar Satyamurthy, and Jorge R. Barrio. "Microstructural Imaging of Neurodegenerative Changes." In PET in the Evaluation of Alzheimer's Disease and Related Disorders, 95–117. New York, NY: Springer New York, 2009. http://dx.doi.org/10.1007/978-0-387-76420-7_5.

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Kepe, Vladimir, Sung-Cheng Huang, Gary W. Small, Nagichettiar Satyamurthy, and Jorge R. Barrio. "Microstructural Imaging of Neurodegenerative Changes." In PET in the Evaluation of Alzheimer's Disease and Related Disorders, 1–23. New York, NY: Springer New York, 2009. http://dx.doi.org/10.1007/b102284_5.

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Rousseau, Dérick. "Microstructural Imaging of Chocolate Confectionery." In Food Engineering Series, 311–33. Cham: Springer International Publishing, 2016. http://dx.doi.org/10.1007/978-3-319-24735-9_10.

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Cahn, R. W., G. Ertl, and J. Heydenreich. "Microstructural Characterization of Materials: An Assessment." In High-Resolution Imaging and Spectrometry of Materials, 419–33. Berlin, Heidelberg: Springer Berlin Heidelberg, 2003. http://dx.doi.org/10.1007/978-3-662-07766-5_10.

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Liu, Songping, Enming Guo, V. M. Levin, and Yu S. Petronyuk. "Measuring Sound Velocities and Anisotropy of Microstructural Units of Laminate Composite Materials by Microacoustical Technique." In Acoustical Imaging, 199–206. Dordrecht: Springer Netherlands, 2004. http://dx.doi.org/10.1007/978-1-4020-2402-3_26.

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Wang, Vicky Y., Alexander J. Wilson, Gregory B. Sands, Alistair A. Young, Ian J. LeGrice, and Martyn P. Nash. "Microstructural Remodelling and Mechanics of Hypertensive Heart Disease." In Functional Imaging and Modeling of the Heart, 382–89. Cham: Springer International Publishing, 2015. http://dx.doi.org/10.1007/978-3-319-20309-6_44.

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Connesson, N., F. Maquin, and F. Pierron. "Dissipative energy: monitoring microstructural evolutions during mechanical tests." In Thermomechanics and Infra-Red Imaging, Volume 7, 59–65. New York, NY: Springer New York, 2011. http://dx.doi.org/10.1007/978-1-4614-0207-7_8.

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Aguilera, José M., and Peter J. Lillford. "Microstructural and Imaging Analyses as Related to Food Engineering." In Food Engineering Series, 23–38. Boston, MA: Springer US, 1997. http://dx.doi.org/10.1007/978-1-4615-6057-9_2.

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Bock, Nicholas A., and Afonso C. Silva. "Visualizing Myeloarchitecture In Vivo with Magnetic Resonance Imaging in Common Marmosets (Callithrix jacchus)." In Microstructural Parcellation of the Human Cerebral Cortex, 221–37. Berlin, Heidelberg: Springer Berlin Heidelberg, 2013. http://dx.doi.org/10.1007/978-3-662-45766-5_8.

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Conference papers on the topic "Microstructural imaging":

1

Shimada, Kazuhiko. "Microstructural lines involving luminescence." In Electronic Imaging 2004, edited by Rudolf L. van Renesse. SPIE, 2004. http://dx.doi.org/10.1117/12.526182.

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Fritzsche, Klaus H., Romuald Brunner, Romy Henze, Hans-Peter Meinzer, and Bram Stieltjes. "Exploration of microstructural abnormalities in borderline personality disorder." In SPIE Medical Imaging. SPIE, 2012. http://dx.doi.org/10.1117/12.911929.

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Clark, Matt, Adam Clare, Paul Dryburgh, Wenqi Li, Rikesh Patel, Don Pieris, Steve Sharples, and Richard Smith. "Spatially resolved acoustic spectroscopy (SRAS) microstructural imaging." In 45TH ANNUAL REVIEW OF PROGRESS IN QUANTITATIVE NONDESTRUCTIVE EVALUATION, VOLUME 38. Author(s), 2019. http://dx.doi.org/10.1063/1.5099705.

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Zeng, Yaping, Jian Xu, Deyong Kang, Shuangmu Zhuo, Xiaoqin zhu, Jiangbo Lin, and Jianxin Chen. "Microstructural imaging of human esophagus using multiphoton microscopy." In International Conference on Photonics and Imaging in Biology and Medicine. Washington, D.C.: OSA, 2017. http://dx.doi.org/10.1364/pibm.2017.w3a.98.

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Bricker, Stephen, J. P. Simmons, Craig Przybyla, and Russell Hardie. "Anomaly detection of microstructural defects in continuous fiber reinforced composites." In IS&T/SPIE Electronic Imaging, edited by Charles A. Bouman and Ken D. Sauer. SPIE, 2015. http://dx.doi.org/10.1117/12.2079679.

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Brusini, Lorenza, Mauro Zucchelli, Cristina Granziera, and Gloria Menegaz. "Microstructural Description of Cerebral Tissues from Diffusion Spectrum Imaging Data." In 2014 IEEE International Conference on Healthcare Informatics (ICHI). IEEE, 2014. http://dx.doi.org/10.1109/ichi.2014.68.

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Kawata, Y., K. Kageyama, N. Niki, K. Umetani, K. Yada, H. Ohamatsu, N. Moriyama, and H. Itoh. "Microstructural analysis of secondary pulmonary lobule imaged by synchrotron radiation micro CT using offset scan mode." In SPIE Medical Imaging, edited by Robert C. Molthen and John B. Weaver. SPIE, 2010. http://dx.doi.org/10.1117/12.845583.

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Afzali, Maryam, Chantal M. W. Tax, Cyrano Chatziantoniou, and Derek K. Jones. "Comparison of Different Tensor Encoding Combinations in Microstructural Parameter Estimation." In 2019 IEEE 16th International Symposium on Biomedical Imaging (ISBI). IEEE, 2019. http://dx.doi.org/10.1109/isbi.2019.8759100.

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Liu, Yueming, Shaojun Zhang, and Weijian Tian. "Microreplication of flexible and stretchable polymer grating sensing elements for microstructural monitoring." In International Symposium on Photoelectronic Detection and Imaging 2009, edited by Xu-yuan Chen, Yue-lin Wang, Zhi-ping Zhou, and Qing-kang Wang. SPIE, 2009. http://dx.doi.org/10.1117/12.835510.

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Wu, Jing, Mohammad S. Alam, KM Rafidh Hassan, Jeffrey C. Suhling, and Pradeep Lall. "Investigation and Comparison of Aging Effects in SAC305 and Doped SAC+X Solders Exposed to Isothermal Aging." In ASME 2020 International Technical Conference and Exhibition on Packaging and Integration of Electronic and Photonic Microsystems. American Society of Mechanical Engineers, 2020. http://dx.doi.org/10.1115/ipack2020-2695.

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Abstract Microstructural evolution occurs in lead free Sn-Ag-Cu (SAC) solder joints exposed to isothermal aging. Such changes lead to degradations in the mechanical properties and creep behavior of the solder, and can result in dramatic reductions in the board level reliability of lead-free electronic assemblies subjected to aging. In our recent research, Scanning Electron Microscopy (SEM) has been used to: (1) monitor aging induced microstructural changes occurring within fixed regions in selected lead-free solder joints, (2) create time-lapse imagery of the microstructure evolution, and (3) analyze the microstructural changes quantitatively and correlate to the observed mechanical behavior evolution. This approach has removed the limitations of many prior studies where aged and non-aged microstructures were taken from two different samples and could only be qualitatively compared. In our current study, the microstructural evolutions were observed in SAC305 (96.5Sn-3.0Ag-0.5Cu) and SAC_Q (SAC+Bi) exposed to isothermal conditions at T = 100 °C and 125 °C for several different regions from several different joints. The microstructures in several fixed regions of interest were recorded after predetermined time intervals of aging, which were 1 hour (up to 270 hours) and 250 hours (up to 7000 hours) for the long-term aging samples. The aging induced changes in microstructure have been correlated with the changes in mechanical behavior measured using uniaxial tensile testing. The area and diameter of each IMC particle were tracked during the aging process using the recorded images and imaging processing software. As expected, the analysis of the evolving SAC305 and SAC+X microstructures showed a significant amount of diffusion of silver and bismuth in the beta-tin matrix during aging. In particular, Ag3Sn particles coalesced during aging leading to a decrease in the number of particles. Any bismuth in the SAC+X microstructure was observed to quickly go into solution, resulting in solid solution strengthening. This primary occurred within the beta-Sn dendrites, but also in the Ag3Sn intermetallic rich regions between dendrites. The presence of bismuth in was also found to slow the diffusion process that coarsens the Ag3Sn IMC particles. The combination solid solution strengthening and a lower diffusion rate for Ag lead to reduced aging effects in the SAC+Bi alloy relative to the SAC305 solder alloy. The SAC_Q alloy was found to have significantly better high temperature mechanical properties relative to SAC305 at all prior aging conditions. In particular, the initial modulus and ultimate tensile strength of SAC305 experienced large degradations during high temperature aging, whereas the same properties of SAC_Q changed only slightly. These changes in mechanical behavior correlated well with the observed increases in the average IMC particle diameter and decreases in the number of IMC particles. The microstructural and material property degradations were especially large for SAC305 during the initial 50 hours of aging.

Reports on the topic "Microstructural imaging":

1

Hiltl, M., C. R. Hagelberg, R. P. Swift, and W. J. Nellis. Microstructural Imaging of Shock-Recovered Berea Sandstone and Quartz Sand Using Scanning Electron Microscopy. Office of Scientific and Technical Information (OSTI), February 2000. http://dx.doi.org/10.2172/792614.

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Asenath-Smith, Emily, Ross Lieblappen, Susan Taylor, Reed Winter, Terry Melendy, Robert Moser, and Robert Haehnel. Observation of crack arrest in ice by high aspect ratio particles during uniaxial compression. Engineer Research and Development Center (U.S.), February 2022. http://dx.doi.org/10.21079/11681/43145.

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In nature, ice frequently contains dissolved solutes or entrapped particles, which modify the microstructure and mechanical properties of ice. Seeking to understand the effect of particle shape and geometry on the mechanical properties of ice, we performed experiments on ice containing 15 wt% silica spheres or rods. Unique to this work was the use of 3-D microstructural imaging in a -10ºC cold room during compressive loading of the sample. The silica particles were present in the ice microstructure as randomly dispersed aggregates within grains and at grain boundaries. While cracks originated in particle-free regions in both sphere- and rod-containing samples, the propagation of cracks was quite different in each type of sample. Cracks propagated uninhibited through aggregates of spherical particles but were observed to arrest at and propagate around aggregates of rods. These results imply that spherical particles do not inhibit grain boundary sliding or increase viscous drag. On the other hand, silica rods were found to span grains, thereby pinning together the microstructure of ice during loading. These results provide insights into mechanisms that can be leveraged to strengthen ice.
3

Aker, P. M. Optical Imaging in Microstructures. Office of Scientific and Technical Information (OSTI), April 2001. http://dx.doi.org/10.2172/833829.

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Stutzman, Paul E., Jeffrey Bullard, and Pan Feng. Quantitative Imaging of Clinker and Cement Microstructure. National Institute of Standards and Technology, April 2015. http://dx.doi.org/10.6028/nist.tn.1877.

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Jablonski, David. DTRT57-09-C-10046 Digital Imaging of Pipeline Mechanical Damage and Residual Stress. Chantilly, Virginia: Pipeline Research Council International, Inc. (PRCI), February 2010. http://dx.doi.org/10.55274/r0011872.

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The purpose of this program was to enhance the characterization of mechanical damage in pipelines through the application of digital eddy current imaging. Lift-off maps can be used to develop quantitative representations of mechanical damage and magnetic permeability maps can be used to determine residual stress patterns around mechanical damage sites. Note that magnetic permeability is also affected by microstructure variations due to plastic deformation and plowing. High-resolution digital images provide an opportunity for automated analysis of both size and shape of damage and a permanent archival record that can be compared against future measurements to detect changes in size or shape of the damage. Also, multiple frequency measurements will enable volumetric and even through-wall imaging at mechanical damage sites to support further risk assessment efforts.
6

Glass, S. J., J. R. Michael, M. J. Readey, S. I. Wright, and D. P. Field. Characterization of microstructure and crack propagation in alumina using orientation imaging microscopy (OIM). December 1996. Office of Scientific and Technical Information (OSTI), December 1996. http://dx.doi.org/10.2172/443200.

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