MULTICENTRE COMPARISON OF IMAGE QUALITY FOR LOW-CONTRAST OBJECTS AND MICROCATHETER TIPS IN X-RAY-GUIDED TREATMENT OF ARTERIOVENOUS MALFORMATION IN THE BRAIN

2015 ◽  
Vol 169 (1-4) ◽  
pp. 325-330
Author(s):  
I. Hernández-Girón ◽  
J. E. M. Mourik ◽  
M. L. Overvelde ◽  
W. J. H. Veldkamp ◽  
D. Zweers ◽  
...  
Keyword(s):  
Image Quality ◽  
Arteriovenous Malformation ◽  
Low Contrast ◽  
X Ray ◽  
The Brain

scholarly journals X-Ray Scatter Correction on Soft Tissue Images for Portable Cone Beam CT

2016 ◽  
Vol 2016 ◽  
pp. 1-12 ◽  
Author(s):  
Sorapong Aootaphao ◽  
Saowapak S. Thongvigitmanee ◽  
Jartuwat Rajruangrabin ◽  
Chalinee Thanasupsombat ◽  
Tanapon Srivongsa ◽  
...  
Keyword(s):  
Soft Tissue ◽  
Image Quality ◽  
Soft Tissues ◽  
Scatter Correction ◽  
Cone Beam ◽  
Ct Number ◽  
Low Contrast ◽  
X Ray ◽  
Cupping Artifacts ◽  
The Brain

Soft tissue images from portable cone beam computed tomography (CBCT) scanners can be used for diagnosis and detection of tumor, cancer, intracerebral hemorrhage, and so forth. Due to large field of view, X-ray scattering which is the main cause of artifacts degrades image quality, such as cupping artifacts, CT number inaccuracy, and low contrast, especially on soft tissue images. In this work, we propose the X-ray scatter correction method for improving soft tissue images. The X-ray scatter correction scheme to estimate X-ray scatter signals is based on the deconvolution technique using the maximum likelihood estimation maximization (MLEM) method. The scatter kernels are obtained by simulating the PMMA sheet on the Monte Carlo simulation (MCS) software. In the experiment, we used the QRM phantom to quantitatively compare with fan-beam CT (FBCT) data in terms of CT number values, contrast to noise ratio, cupping artifacts, and low contrast detectability. Moreover, the PH3 angiography phantom was also used to mimic human soft tissues in the brain. The reconstructed images with our proposed scatter correction show significant improvement on image quality. Thus the proposed scatter correction technique has high potential to detect soft tissues in the brain.

Analytical Electron Microscopy (AEM) of Meningeal Cells Exposed to Particulate Cobalt During Studies of Experimental Epilepsy

1982 ◽  
Vol 40 ◽  
pp. 186-187
Author(s):  
R.G. Frederickson ◽  
R.G. Ulrich ◽  
J.L. Culberson
Keyword(s):  
Electron Microscopy ◽  
Analytical Electron Microscopy ◽  
Experimental Epilepsy ◽  
Metallic Cobalt ◽  
Experimental Animals ◽  
X Ray ◽  
Brain Surface ◽  
Meningeal Cells ◽  
Analytical Electron ◽  
The Brain

Metallic cobalt acts as an epileptogenic agent when placed on the brain surface of some experimental animals. The mechanism by which this substance produces abnormal neuronal discharge is unknown. One potentially useful approach to this problem is to study the cellular and extracellular distribution of elemental cobalt in the meninges and adjacent cerebral cortex. Since it is possible to demonstrate the morphological localization and distribution of heavy metals, such as cobalt, by correlative x-ray analysis and electron microscopy (i.e., by AEM), we are using AEM to locate and identify elemental cobalt in phagocytic meningeal cells of young 80-day postnatal opossums following a subdural injection of cobalt particles.

Image Quality Analysis of X-ray Grating Interferometer Using Integrating-bucket Method

2020 ◽  
Vol 64 (2) ◽  
pp. 20503-1-20503-5
Author(s):  
Faiz Wali ◽  
Shenghao Wang ◽  
Ji Li ◽  
Jianheng Huang ◽  
Yaohu Lei ◽  
...  
Keyword(s):  
Image Quality ◽  
Phase Contrast ◽  
Quality Analysis ◽  
Phase Contrast Imaging ◽  
Phase Image ◽  
Contrast Imaging ◽  
High Quality ◽  
Image Quality Analysis ◽  
X Ray ◽  
Grating Interferometer

Abstract Grating-based x-ray phase-contrast imaging has the potential to enhance image quality and provide inner structure details non-destructively. In this work, using grating-based x-ray phase-contrast imaging system and employing integrating-bucket method, the quantitative expressions of signal-to-noise ratios due to photon statistics and mechanical error are analyzed in detail. Photon statistical noise and mechanical error are the main sources affecting the image noise in x-ray grating interferometry. Integrating-bucket method is a new phase extraction method translated to x-ray grating interferometry; hence, its image quality analysis would be of great importance to get high-quality phase image. The authors’ conclusions provide an alternate method to get high-quality refraction signal using grating interferometer, and hence increases applicability of grating interferometry in preclinical and clinical usage.

A Systematic Review of Double Low-dose CT Pulmonary Angiography in Pulmonary Embolism

2019 ◽  
Vol 15 (5) ◽  
pp. 453-460 ◽  
Author(s):  
Sultan Aldosari ◽  
Zhonghua Sun
Keyword(s):  
Systematic Review ◽  
Pulmonary Embolism ◽  
Image Quality ◽  
Radiation Dose ◽  
Contrast Medium ◽  
Low Dose ◽  
Pulmonary Angiography ◽  
Ct Pulmonary Angiography ◽  
Low Contrast ◽  
Low Contrast Medium

Background: The aim of this study is to perform a systematic review of the feasibility and clinical application of double low-dose CT pulmonary angiography (CTPA) in the diagnosis of patients with suspected pulmonary embolism. Discussion: A total of 13 studies were found to meet selection criteria reporting both low radiation dose (70 or 80 kVp versus 100 or 120 kVp) and low contrast medium dose CTPA protocols. Lowdose CTPA resulted in radiation dose reduction from 29.6% to 87.5% in 12 studies (range: 0.4 to 23.5 mSv), while in one study, radiation dose was increased in the dual-energy CT group when compared to the standard 120 kVp group. CTPA with use of low contrast medium volume (range: 20 to 75 ml) was compared to standard CTPA (range: 50 to 101 ml) in 12 studies with reduction between 25 and 67%, while in the remaining study, low iodine concentration was used with 23% dose reduction achieved. Quantitative assessment of image quality (in terms of signal-to-noise ratio and contrast-to-noise ratio) showed that low-dose CTPA was associated with higher, lower and no change in image quality in 3, 3 and 6 studies, respectively when compared to the standard CTPA protocol. The subjective assessment indicated similar image quality in 11 studies between low-dose and standard CTPA groups, and improved image quality in 1 study with low-dose CTPA. Conclusion: This review shows that double low-dose CTPA is feasible in the diagnosis of pulmonary embolism with significant reductions in both radiation and contrast medium doses, without compromising diagnostic image quality.

scholarly journals Spinal vertebrae localization and analysis on disproportionality in curvature using radiography—a comprehensive review

2021 ◽  
Vol 2021 (1) ◽  
Author(s):  
Joddat Fatima ◽  
Muhammad Usman Akram ◽  
Amina Jameel ◽  
Adeel Muzaffar Syed
Keyword(s):  
Spinal Cord ◽  
Template Matching ◽  
Human Anatomy ◽  
Comprehensive Overview ◽  
Low Contrast ◽  
Active Shape Models ◽  
Harris Corner ◽  
Illumination Changes ◽  
The Central Nervous System ◽  
The Brain

AbstractIn human anatomy, the central nervous system (CNS) acts as a significant processing hub. CNS is clinically divided into two major parts: the brain and the spinal cord. The spinal cord assists the overall communication network of the human anatomy through the brain. The mobility of body and the structure of the whole skeleton is also balanced with the help of the spinal bone, along with reflex control. According to the Global Burden of Disease 2010, worldwide, back pain issues are the leading cause of disability. The clinical specialists in the field estimate almost 80% of the population with experience of back issues. The segmentation of the vertebrae is considered a difficult procedure through imaging. The problem has been catered by different researchers using diverse hand-crafted features like Harris corner, template matching, active shape models, and Hough transform. Existing methods do not handle the illumination changes and shape-based variations. The low-contrast and unclear view of the vertebrae also makes it difficult to get good results. In recent times, convolutional nnural Network (CNN) has taken the research to the next level, producing high-accuracy results. Different architectures of CNN such as UNet, FCN, and ResNet have been used for segmentation and deformity analysis. The aim of this review article is to give a comprehensive overview of how different authors in different times have addressed these issues and proposed different mythologies for the localization and analysis of curvature deformity of the vertebrae in the spinal cord.

scholarly journals A review of nanotechnology with an emphasis on Nanoplex

2015 ◽  
Vol 51 (2) ◽  
pp. 255-263
Author(s):  
Rupali Nanasaheb Kadam ◽  
Raosaheb Sopanrao Shendge ◽  
Vishal Vijay Pande
Keyword(s):  
Drug Delivery ◽  
Drug Delivery Systems ◽  
Drug Loading ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Conventional Drug ◽  
Anionic Drugs ◽  
Oppositely Charged ◽  
The Brain

<p>The use of nanotechnology based on the development and fabrication of nanostructures is one approach that has been employed to overcome the challenges involved with conventional drug delivery systems. Formulating Nanoplex is the new trend in nanotechnology. A nanoplex is a complex formed by a drug nanoparticle with an oppositely charged polyelectrolyte. Both cationic and anionic drugs form complexes with oppositely charged polyelectrolytes. Compared with other nanostructures, the yield of Nanoplex is greater and the complexation efficiency is better. Nanoplex are also easier to prepare. Nanoplex formulation is characterized through the production yield, complexation efficiency, drug loading, particle size and zeta potential using scanning electron microscopy, differential scanning calorimetry, X-ray diffraction and dialysis studies. Nanoplex have wide-ranging applications in different fields such as cancer therapy, gene drug delivery, drug delivery to the brain and protein and peptide drug delivery.</p>

scholarly journals Preliminary photographs and improved positives: discovering the New York Public Library’s Arctic Exploration album

2021 ◽  
Vol 9 (1) ◽  
Author(s):  
Elena Basso ◽  
Federica Pozzi ◽  
Jessica Keister ◽  
Elizabeth Cronin
Keyword(s):  
New York ◽  
Fiber Optics ◽  
Public Library ◽  
Extreme Environment ◽  
The Arctic ◽  
Low Contrast ◽  
X Ray ◽  
Full Characterization ◽  
New York Public Library ◽  
Shed Light

AbstractIn the late 19th and early 20th centuries, original photographs were sent to publishers so that they could be reproduced in print. The photographs often needed to be reworked with overpainting and masking, and such modifications were especially necessary for low-contrast photographs to be reproduced as a letterpress halftone. As altered objects, many of these marked-up photographs were simply discarded after use. An album at The New York Public Library, however, contains 157 such photographs, all relating to the Jackson–Harmsworth expedition to Franz Josef Land, from 1894 to 1897. Received as gifts from publishers, the photographs are heavily retouched with overpainting and masking, as well as drawn and collaged elements. The intense level of overpainting on many of the photographs, but not on others, raised questions about their production and alteration. Jackson’s accounts attested to his practice of developing and printing photographs on site, testing different materials and techniques—including platino-bromide and silver-gelatin papers—to overcome the harsh environmental conditions. In this context, sixteen photographs from the album were analyzed through a combination of non-invasive and micro-invasive techniques, including X-ray fluorescence (XRF) spectroscopy, fiber optics reflectance spectroscopy (FORS), Raman and Fourier-transform infrared (FTIR) spectroscopies, and scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM/EDS). This analytical campaign aimed to evaluate the possible residual presence of silver halides in any of the preliminary and improved photographs. The detection of these compounds would be one of several factors supporting a hypothesis that some of the photographs in the album were indeed printed on site, in the Arctic, and, as a result, may have been impacted by the extreme environment. Additional goals of the study included the evaluation of the extent of retouching, providing a full characterization of the pigments and dyes used in overpainted prints, and comparing the results with contemporaneous photographic publications that indicate which coloring materials were available at the time. Further analyses shed light on the organic components present in the binders and photographic emulsions. This research has increased our knowledge of photographic processes undertaken in a hostile environment such as the Arctic, and shed light on the technical aspects of photographically illustrating books during the late 19th and early 20th centuries.

scholarly journals Multidisciplinary Approach to Suspected Sudden Death Caused by Arteriovenous Malformation Rupture: A Case Report

Medicina ◽  
2021 ◽  
Vol 57 (7) ◽  
pp. 644
Author(s):  
Federico Giuseppe Patanè ◽  
Massimiliano Esposito ◽  
Andrea Giovanni Musumeci ◽  
Monica Palermo ◽  
Marco Torrisi ◽  
...  
Keyword(s):  
Arteriovenous Malformation ◽  
Cause Of Death ◽  
Venous Malformation ◽  
Healthy Woman ◽  
Unexpected Death ◽  
Medical Problems ◽  
Variable Diameter ◽  
Life Threatening ◽  
Brain Avms ◽  
The Brain

Arteriovenous malformations (AVMs) are rare congenital conditions with a prevalence of less than 1% and are mostly asymptomatic. However, these malformations can suddenly cause intense pain or bleeding, leading to life-threatening medical problems. This report presents a case of an unexpected death in a 37-year-old previously healthy woman due to an intra-cerebellum arteriovenous malformation rupture identified during autopsy. While infective processes where preliminarily excluded, a Post Mortem Computed Tomography (PMCT) identified a tetra ventricular hemorrhage and intra-cerebellum hemorrhage. Toxicological examination was negative for most substances of abuse. During autopsy an intense hemorrhagic infiltrate in the subarachnoid space was observed. After formalin fixation of the brain the cerebellum showed hemorrhagic infarction on fourth ventricle sides, as well as several small reddish infarctions across the entire cerebellum parenchyma. Histological examination of the brain and cerebellum showed a suffusion of erythrocytes in the sub-arachnoid region. Evidence of an arterio-venous malformation, with several intertwine vessels of variable diameter, surrounded by hemorrhagic evidence. The autopsy played a crucial role in identifying the location and the possibly affected vessel, as well as defining the cause of death. It is necessary to have a greater number of autopsies to make an epidemiological contribution. Furthermore, it is crucial to create a multicenter data network with other authors from other departments to improve information about epidemiological, clinical, diagnostic and therapeutic data. Most brain AVMs as cause of death are often undiscovered.

scholarly journals Correlation of image quality parameters with tube voltage in X-ray dark-field chest radiography: a phantom study

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Andreas P. Sauter ◽  
Jana Andrejewski ◽  
Manuela Frank ◽  
Konstantin Willer ◽  
Julia Herzen ◽  
...  
Keyword(s):  
Image Quality ◽  
Imaging Modality ◽  
Signal Strength ◽  
Dark Field ◽  
Tube Voltage ◽  
X Ray ◽  
Dose Area Product ◽  
Dark Field Imaging ◽  
Field Imaging

AbstractGrating-based X-ray dark-field imaging is a novel imaging modality with enormous technical progress during the last years. It enables the detection of microstructure impairment as in the healthy lung a strong dark-field signal is present due to the high number of air-tissue interfaces. Using the experience from setups for animal imaging, first studies with a human cadaver could be performed recently. Subsequently, the first dark-field scanner for in-vivo chest imaging of humans was developed. In the current study, the optimal tube voltage for dark-field radiography of the thorax in this setup was examined using an anthropomorphic chest phantom. Tube voltages of 50–125 kVp were used while maintaining a constant dose-area-product. The resulting dark-field and attenuation radiographs were evaluated in a reader study as well as objectively in terms of contrast-to-noise ratio and signal strength. We found that the optimum tube voltage for dark-field imaging is 70 kVp as here the most favorable combination of image quality, signal strength, and sharpness is present. At this voltage, a high image quality was perceived in the reader study also for attenuation radiographs, which should be sufficient for routine imaging. The results of this study are fundamental for upcoming patient studies with living humans.

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