X-ray dark-field tomography reveals tooth cracks

AbstractCracked tooth syndrome (CTS) is a common clinical finding for teeth, it affects about 5% of all adults each year. The finding of CTS is favored by several risk factors such as restorations, bruxism, occlusion habits, and age. Treatment options range, depending on the severity, from no treatment at all to tooth extraction. Early diagnosis of CTS is crucial for optimal treatment and symptom reduction. There is no standard procedure for an evidence-based diagnosis up to date. The diagnosis is a challenge by the fact that the symptoms, including pain and sensitivity to temperature stimuli, cannot be clearly linked to the disease. Commonly used visual inspection does not provide in-depth information and is limited by the resolution of human eyes. This can be overcome by magnifying optics or contrast enhancers, but the diagnosis will still strongly rely on the practicians experience. Other methods are symptom reproduction with percussions, thermal pulp tests or bite tests. Dental X-ray radiography, as well as computed tomography, rarely detect cracks as they are limited in resolution. Here, we investigate X-ray dark-field tomography (XDT) for the detection of tooth microcracks. XDT simultaneously detects X-ray small-angle scattering (SAXS) in addition to the attenuation, whereas it is most sensitive to the micrometer regime. Since SAXS originates from gradients in electron density, the signal is sensitive to the sample morphology. Microcracks create manifold interfaces which lead to a strong signal. Therefore, it is possible to detect structural changes originating from subpixel-sized structures without directly resolving them. Together with complementary attenuation information, which visualizes comparatively large cracks, cracks are detected on all length-scales for a whole tooth in a non-destructive way. Hence, this proof-of principle study on three ex-vivo teeth shows the potential of X-ray scattering for evidence-based detection of cracked teeth.

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Varying Collimation for Dark-Field Extraction

International Journal of Biomedical Imaging ◽

10.1155/2009/847537 ◽

2009 ◽

Vol 2009 ◽

pp. 1-7 ◽

Cited By ~ 1

Author(s):

Ge Wang ◽

Wenxiang Cong ◽

Haiou Shen ◽

Yu Zou

Keyword(s):

Aspect Ratio ◽

Small Angle ◽

Dark Field ◽

Small Angle Scattering ◽

Primary Beam ◽

Scattering Data ◽

Projection Data ◽

X Ray ◽

X Ray Imaging ◽

Angle Scattering

Although x-ray imaging is widely used in biomedical applications, biological soft tissues have small density changes, leading to low contrast resolution for attenuation-based x-ray imaging. Over the past years, x-ray small-angle scattering was studied as a new contrast mechanism to enhance subtle structural variation within the soft tissue. In this paper, we present a detection method to extract this type of x-ray scattering data, which are also referred to as dark-field signals. The key idea is to acquire an x-ray projection multiple times with varying collimation before an x-ray detector array. The projection data acquired with a collimator of a sufficiently high collimation aspect ratio contain mainly the primary beam with little scattering, while the data acquired with an appropriately reduced collimation aspect ratio include both the primary beam and small-angle scattering signals. Then, analysis of these corresponding datasets will produce desirable dark-field signals; for example, via digitally subtraction. In the numerical experiments, the feasibility of our dark-field detection technology is demonstrated in Monte Carlo simulation. The results show that the acquired dark field signals can clearly reveal the structural information of tissues in terms of Rayleigh scattering characteristics.

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Small-angle scattering: a view on the properties, structures and structural changes of biological macromolecules in solution

Quarterly Reviews of Biophysics ◽

10.1017/s0033583503003871 ◽

2003 ◽

Vol 36 (2) ◽

pp. 147-227 ◽

Cited By ~ 378

Author(s):

Michel H. J. Koch ◽

Patrice Vachette ◽

Dmitri I. Svergun

Keyword(s):

High Resolution ◽

Neutron Scattering ◽

Small Angle ◽

Structure Factor ◽

Structural Changes ◽

Biological Macromolecules ◽

Time Resolved ◽

Scattering Intensity ◽

X Ray ◽

Angle Scattering

1. Introduction 1482. Basics of X-ray and neutron scattering 1492.1 Elastic scattering of electromagnetic radiation by a single electron 1492.2 Scattering by assemblies of electrons 1512.3 Anomalous scattering and long wavelengths 1532.4 Neutron scattering 1532.5 Transmission and attenuation 1553. Small-angle scattering from solutions 1563.1 Instrumentation 1563.2 The experimental scattering pattern 1573.3 Basic scattering functions 1593.4 Global structural parameters 1613.4.1 Monodisperse systems 1613.4.2 Polydisperse systems and mixtures 1633.5 Characteristic functions 1644. Modelling 1664.1 Spherical harmonics 1664.2 Shannon sampling 1694.3 Shape determination 1704.3.1 Modelling with few parameters: molecular envelopes 1714.3.2 Modelling with many parameters: bead models 1734.4 Modelling domain structure and missing parts of high-resolution models 1784.5 Computing scattering patterns from atomic models 1844.6 Rigid-body refinement 1875. Applications 1905.1 Contrast variation studies of ribosomes 1905.2 Structural changes and catalytic activity of the allosteric enzyme ATCase 1916. Interactions between molecules in solution 2036.1 Linearizing the problem for moderate interactions: the second virial coefficient 2046.2 Determination of the structure factor 2057. Time-resolved measurements 2118. Conclusions 2159. Acknowledgements 21610. References 216A self-contained presentation of the main concepts and methods for interpretation of X-ray and neutron-scattering patterns of biological macromolecules in solution, including a reminder of the basics of X-ray and neutron scattering and a brief overview of relevant aspects of modern instrumentation, is given. For monodisperse solutions the experimental data yield the scattering intensity of the macromolecules, which depends on the contrast between the solvent and the particles as well as on their shape and internal scattering density fluctuations, and the structure factor, which is related to the interactions between macromolecules. After a brief analysis of the information content of the scattering intensity, the two main approaches for modelling the shape and/or structure of macromolecules and the global minimization schemes used in the calculations are presented. The first approach is based, in its more advanced version, on the spherical harmonics approximation and relies on few parameters, whereas the second one uses bead models with thousands of parameters. Extensions of bead modelling can be used to model domain structure and missing parts in high-resolution structures. Methods for computing the scattering patterns from atomic models including the contribution of the hydration shell are discussed and examples are given, which also illustrate that significant differences sometimes exist between crystal and solution structures. These differences are in some cases explainable in terms of rigid-body motions of parts of the structures. Results of two extensive studies – on ribosomes and on the allosteric protein aspartate transcarbamoylase – illustrate the application of the various methods. The unique bridge between equilibrium structures and thermodynamic or kinetic aspects provided by scattering techniques is illustrated by modelling of intermolecular interactions, including crystallization, based on an analysis of the structure factor and recent time-resolved work on assembly and protein folding.

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Structural changes of F1ATPase detected by neutron- and X-ray small angle scattering

Physica B Condensed Matter ◽

10.1016/0921-4526(89)90710-2 ◽

1989 ◽

Vol 156-157 ◽

pp. 485-488 ◽

Cited By ~ 3

Author(s):

T. Nawroth ◽

A. Neidhardt ◽

K. Dose ◽

H. Conrad ◽

B. Munk ◽

...

Keyword(s):

Small Angle ◽

Structural Changes ◽

Small Angle Scattering ◽

X Ray ◽

Angle Scattering

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X-ray dark-field radiography for in situ gout diagnosis by means of an ex vivo animal study

Scientific Reports ◽

10.1038/s41598-021-98151-0 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Josef Scholz ◽

Nathalie Roiser ◽

Eva-Maria Braig ◽

Christian Petrich ◽

Lorenz Birnbacher ◽

...

Keyword(s):

Ex Vivo ◽

Clinical Signs ◽

Premature Mortality ◽

Dark Field ◽

Invasive Approach ◽

X Ray ◽

Non Invasive ◽

Diagnostic Sensitivity And Specificity ◽

Msu Crystals

AbstractGout is the most common form of inflammatory arthritis, caused by the deposition of monosodium urate (MSU) crystals in peripheral joints and tissue. Detection of MSU crystals is essential for definitive diagnosis, however the gold standard is an invasive process which is rarely utilized. In fact, most patients are diagnosed or even misdiagnosed based on manifested clinical signs, as indicated by the unchanged premature mortality among gout patients over the past decade, although effective treatment is now available. An alternative, non-invasive approach for the detection of MSU crystals is X-ray dark-field radiography. In our work, we demonstrate that dark-field X-ray radiography can detect naturally developed gout in animals with high diagnostic sensitivity and specificity based on the in situ measurement of MSU crystals. With the results of this study as a potential basis for further research, we believe that X-ray dark-field radiography has the potential to substantially improve gout diagnostics.

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High-angle annular dark-field imaging on a TEM/STEM system

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s042482010015304x ◽

1989 ◽

Vol 47 ◽

pp. 214-215

Author(s):

Max T. Otten

Keyword(s):

Dark Field ◽

High Angle ◽

X Ray ◽

Image Recording ◽

Dark Field Imaging ◽

Angle Scattering ◽

Annular Dark Field ◽

Time Required ◽

Field Imaging ◽

Camera Length

High-Angle Annular Dark-Field (HAADF) imaging is a technique that brings out compositional contrasts with a sensitivity about 106 times higher than X-ray images, thereby allowing image recording in normal STEM exposure times (a matter of minutes) instead of the time required for X-ray images (usually several hours). The technique uses those electrons that have undergone high-angle scattering. These have Z dependence and are therefore very effective in bringing out compositional contrasts.Much of the HAADF work to date has been performed on dedicated STEMs. However, the technique can be performed as well with the annular Dark-Field detector on several types of TEM/STEM systems. Such systems have the added advantage of camera-length flexibility, providing a range of images with different kinds of information from the same detector.

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Ex Vivo Perfusion-Simulation Measurements of Microbubbles as a Scattering Contrast Agent for Grating-Based X-Ray Dark-Field Imaging

PLoS ONE ◽

10.1371/journal.pone.0129512 ◽

2015 ◽

Vol 10 (7) ◽

pp. e0129512 ◽

Cited By ~ 9

Author(s):

Astrid Velroyen ◽

Martin Bech ◽

Arne Tapfer ◽

Andre Yaroshenko ◽

Mark Müller ◽

...

Keyword(s):

Contrast Agent ◽

Ex Vivo ◽

Dark Field ◽

X Ray ◽

Ex Vivo Perfusion ◽

Dark Field Imaging ◽

Field Imaging

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X-ray phase-contrast tomography with a compact laser-driven synchrotron source

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.1500938112 ◽

2015 ◽

Vol 112 (18) ◽

pp. 5567-5572 ◽

Cited By ~ 48

Author(s):

Elena Eggl ◽

Simone Schleede ◽

Martin Bech ◽

Klaus Achterhold ◽

Roderick Loewen ◽

...

Keyword(s):

Large Scale ◽

Biomedical Application ◽

Ex Vivo ◽

Small Animal ◽

Dark Field ◽

Light Sources ◽

X Rays ◽

Synchrotron Source ◽

X Ray ◽

Multimodal Ct

Between X-ray tubes and large-scale synchrotron sources, a large gap in performance exists with respect to the monochromaticity and brilliance of the X-ray beam. However, due to their size and cost, large-scale synchrotrons are not available for more routine applications in small and medium-sized academic or industrial laboratories. This gap could be closed by laser-driven compact synchrotron light sources (CLS), which use an infrared (IR) laser cavity in combination with a small electron storage ring. Hard X-rays are produced through the process of inverse Compton scattering upon the intersection of the electron bunch with the focused laser beam. The produced X-ray beam is intrinsically monochromatic and highly collimated. This makes a CLS well-suited for applications of more advanced––and more challenging––X-ray imaging approaches, such as X-ray multimodal tomography. Here we present, to our knowledge, the first results of a first successful demonstration experiment in which a monochromatic X-ray beam from a CLS was used for multimodal, i.e., phase-, dark-field, and attenuation-contrast, X-ray tomography. We show results from a fluid phantom with different liquids and a biomedical application example in the form of a multimodal CT scan of a small animal (mouse, ex vivo). The results highlight particularly that quantitative multimodal CT has become feasible with laser-driven CLS, and that the results outperform more conventional approaches.

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X-ray diffraction reveals blunt-force loading threshold for nanoscopic structural change in ex vivo neuronal tissues

Journal of Synchrotron Radiation ◽

10.1107/s1600577518015035 ◽

2019 ◽

Vol 26 (1) ◽

pp. 89-95 ◽

Cited By ~ 2

Author(s):

Joseph Orgel ◽

Rama S. Madhurapantula ◽

Ashley Eidsmore ◽

Meng Wang ◽

Pavel Dutov ◽

...

Keyword(s):

Structural Changes ◽

Mechanical Load ◽

Ex Vivo ◽

Experimental Methodology ◽

Alternative Methods ◽

X Ray Diffraction ◽

Blunt Force ◽

X Ray ◽

Force Loading ◽

Packing Structure

An ex vivo blunt-force loading experiment is reported that may, in the future, provide insight into the molecular structural changes occurring in load-induced conditions such as traumatic brain injury (TBI). TBI appears to manifest in changes in multiple structures and elements within the brain and nervous system. Individuals with a TBI may suffer from cognitive and/or behavioral impairments which can adversely affect their quality of life. Information on the injury threshold of tissue loading for mammalian neurons is critical in the development of a quantified neuronal-level dose-response model. Such a model could aid in the discovery of enhanced methods for TBI detection, treatment and prevention. Currently, thresholds of mechanical load leading to direct force-coupled nanostructural changes in neurons are unknown. In this study, we make use of the fact that changes in the structure and periodicity of myelin may indicate neurological damage and can be detected with X-ray diffraction (XRD). XRD allows access to a nanoscopic resolution range not readily achieved by alternative methods, nor does the experimental methodology require chemical sample fixation. In this study, XRD was used to evaluate the affects of controlled mechanical loading on myelin packing structure in ex vivo optic nerve samples. By using a series of crush tests on isolated optic nerves a quantified baseline for mechanical load was found to induce changes in the packing structure of myelin. To the authors' knowledge, this is the first report of its kind.

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