scholarly journals Reflection-Mode Ultrasound Computed Tomography Based on Wavelet Processing for High-Contrast Anatomical and Morphometric Imaging

2021 ◽  
Vol 11 (20) ◽  
pp. 9368
Author(s):  
Elise Doveri ◽  
Laurent Sabatier ◽  
Vincent Long ◽  
Philippe Lasaygues
Keyword(s):  
Computed Tomography ◽  
Soft Tissues ◽  
Ex Vivo ◽  
Ultrasonic Waves ◽  
Reflection Mode ◽  
Coded Excitation ◽  
Ultrasonic Signals ◽  
Ultrasound Computed Tomography ◽  
Slice Imaging ◽  
Transverse Slice

Medical B-mode ultrasound is widely used for the examination of children’s limbs, including soft tissue, muscle, and bone. However, for the accurate examination of the bone only, it is often replaced by more restrictive clinical modalities. Several authors have investigated ultrasonic imaging of bone to assess cortical thickness and/or to estimate the wave velocity through the internal structure. The present work focuses on the transverse slice imaging process using reflection-mode ultrasound computed tomography (USCT). The method is valid for imaging soft tissues with similar acoustic impedances, but in the presence of bone, the higher contrasts alter the propagation of ultrasonic waves and reduce the contrast-to-noise ratio (CNR). There is a need to change the methods used for the processing of ultrasonic signals. Our group has developed a wavelet-based coded excitation (WCE) method to process information in frequency and time. The objective of this study is to use the method to improve reflection-mode USCT, at low ultrasonic intensities, to better address organ morphometry. Experimental results on a newborn arm phantom and on an ex vivo chicken drumstick are presented, and the usefulness of this WCE-mode USCT is discussed.

scholarly journals Correlation of Micro-Computed Tomography Assessment of Valvular Mineralisation with Histopathological and Immunohistochemical Features of Calcific Aortic Valve Disease

2019 ◽  
Vol 9 (1) ◽  
pp. 29
Author(s):  
Guillermo Solache-Berrocal ◽  
Ana María Barral-Varela ◽  
Sheila Areces-Rodríguez ◽  
Alejandro Junco-Vicente ◽  
Aitana Vallina-Álvarez ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Aortic Valve ◽  
Molecular Mechanisms ◽  
Soft Tissues ◽  
Ex Vivo ◽  
Developed Countries ◽  
Macrophage Infiltration ◽  
Micro Computed Tomography ◽  
Calcific Aortic Valve Disease ◽  
Calcium Deposits

Aortic valve stenosis is a serious disease with increasing prevalence in developed countries. Research aimed at uncovering the molecular mechanisms behind its main cause, aortic valve calcification, is thus crucial for the development of future therapies. It is frequently difficult to measure the extent of mineralisation in soft tissues and some methods require the destruction of the sample. Micro-computed tomography (µCT), a non-destructive technique, was used to quantify the density and volume of calcium deposits on cusps from 57 explanted aortic valves. Conventional and immunostaining techniques were used to characterise valve tissue degeneration and the inflammatory and osteogenic stage with several markers. Although most of the analysed cusps came from severe stenosis patients, the µCT parameter bone volume/tissue volume ratio distinguished several degrees of mineralisation that correlated with the degree of structural change in the tissue and the amount of macrophage infiltration as determined by CD68 immunohistochemistry. Interestingly, exosomal markers CD63 and Alix co-localised with macrophage infiltration surrounding calcium deposits, suggesting that those vesicles could be produced at least in part by these immune cells. In conclusion, we have shown that the ex vivo assessment of aortic valve mineralisation with µCT reflects the molecular and cellular changes in pathological valves during progression towards stenosis. Thus, our results give additional validity to quantitative μCT as a convenient laboratory tool for basic research on this type of cardiovascular calcification.

scholarly journals Dual-Modality Imaging of the Human Finger Joint Systems by Using Combined Multispectral Photoacoustic Computed Tomography and Ultrasound Computed Tomography

2016 ◽  
Vol 2016 ◽  
pp. 1-7 ◽  
Author(s):  
Yubin Liu ◽  
Yating Wang ◽  
Zhen Yuan
Keyword(s):  
Computed Tomography ◽  
Soft Tissues ◽  
Imaging System ◽  
Finger Joint ◽  
Dual Modality ◽  
Finger Joints ◽  
Ultrasound Computed Tomography ◽  
Imaging Results ◽  
Dual Modality Imaging ◽  
Human Finger

We developed a homemade dual-modality imaging system that combines multispectral photoacoustic computed tomography and ultrasound computed tomography for reconstructing the structural and functional information of human finger joint systems. The fused multispectral photoacoustic-ultrasound computed tomography (MPAUCT) system was examined by the phantom andin vivoexperimental tests. The imaging results indicate that the hard tissues such as the bones and the soft tissues including the blood vessels, the tendon, the skins, and the subcutaneous tissues in the finger joints systems can be effectively recovered by using our multimodality MPAUCT system. The developed MPAUCT system is able to provide us with more comprehensive information of the human finger joints, which shows its potential for characterization and diagnosis of bone or joint diseases.

scholarly journals A Review of Ex Vivo X-ray Microfocus Computed Tomography-Based Characterization of the Cardiovascular System

2021 ◽  
Vol 22 (6) ◽  
pp. 3263
Author(s):  
Lisa Leyssens ◽  
Camille Pestiaux ◽  
Greet Kerckhofs
Keyword(s):  
Computed Tomography ◽  
Soft Tissues ◽  
Ex Vivo ◽  
Image Resolution ◽  
Tissue Preparation ◽  
X Ray ◽  
Spatial Image ◽  
Microfocus Computed Tomography

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.

Atherosclerotic plaque imaging using phase-contrast X-ray computed tomography

2008 ◽  
Vol 294 (2) ◽  
pp. H1094-H1100 ◽  
Author(s):  
Masakazu Shinohara ◽  
Tomoya Yamashita ◽  
Hideto Tawa ◽  
Masafumi Takeda ◽  
Naoto Sasaki ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Atherosclerotic Plaque ◽  
Phase Contrast ◽  
Soft Tissues ◽  
Ex Vivo ◽  
Mass Density ◽  
Specific Mass ◽  
X Ray ◽  
Coronary Syndrome ◽  
Luminal Narrowing

Reliable, noninvasive imaging modalities to characterize plaque components are clinically desirable for detecting unstable coronary plaques, which cause acute coronary syndrome. Although recent clinical developments in computed tomography (CT) have enabled the visualization of luminal narrowing and calcified plaques in coronary arteries, the identification of noncalcified plaque components remains difficult. Phase-contrast X-ray CT imaging has great potentials to reveal the structures inside biological soft tissues, because its sensitivity to light elements is almost 1,000 times greater than that of absorption-contrast X-ray imaging. Moreover, a specific mass density of tissue can be estimated using phase-contrast X-ray CT. Ex vivo phase-contrast X-ray CT was performed using a synchrotron radiation source (SPring-8, Japan) to investigate atherosclerotic plaque components of apolipoprotein E-deficient mice. Samples were also histologically analyzed. Phase-contrast X-ray CT at a spatial resolution of 10–20 μm revealed atherosclerotic plaque components easily, and thin fibrous caps were detected. The specific mass densities of these plaque components were quantitatively estimated. The mass density of lipid area was significantly lower (1.011 ± 0.001766 g/ml) than that of smooth muscle area or collagen area (1.057 ± 0.001407 and 1.080 ± 0.001794 g/ml, respectively). Moreover, the three-dimensional assessment of plaques could provide their anatomical information. Phase-contrast X-ray CT can estimate the tissue mass density of atherosclerotic plaques and detect lipid-rich areas. It can be a promising noninvasive technique for the investigation of plaque components and detection of unstable coronary plaques.

Comparison of Four Forward Models for Breast Imaging in Ultrasound Computed Tomography

2019 ◽  
Vol 28 (4) ◽  
pp. 805-816 ◽  
Author(s):  
Ruijing Li ◽  
Houjin Chen ◽  
Yahui Peng ◽  
Jupeng Li
Keyword(s):  
Computed Tomography ◽  
Breast Imaging ◽  
Forward Models ◽  
Ultrasound Computed Tomography

scholarly journals Porcine Ex Vivo Liver Phantom for Dynamic Contrast-Enhanced Computed Tomography

2011 ◽  
Vol 46 (9) ◽  
pp. 586-593 ◽  
Author(s):  
Scott M. Thompson ◽  
Juan C. Ramirez-Giraldo ◽  
Bruce Knudsen ◽  
Joseph P. Grande ◽  
Jodie A. Christner ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Ex Vivo ◽  
Dynamic Contrast Enhanced ◽  
Contrast Enhanced ◽  
Enhanced Computed Tomography ◽  
Liver Phantom ◽  
Contrast Enhanced Computed Tomography

scholarly journals Cross-sectional anatomy, computed tomography, and magnetic resonance imaging of the banded houndshark (Triakis scyllium)

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Sang Wha Kim ◽  
Adams Hei Long Yuen ◽  
Cherry Tsz Ching Poon ◽  
Joon Oh Hwang ◽  
Chang Jun Lee ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Computed Tomography ◽  
Magnetic Resonance ◽  
Soft Tissues ◽  
Imaging Techniques ◽  
Evolutionary Developmental Biology ◽  
Phylogenetic Position ◽  
Ct Scanner ◽  
Resonance Imaging ◽  
Cross Sectional

AbstractDue to their important phylogenetic position among extant vertebrates, sharks are an invaluable group in evolutionary developmental biology studies. A thorough understanding of shark anatomy is essential to facilitate these studies and documentation of this iconic taxon. With the increasing availability of cross-sectional imaging techniques, the complicated anatomy of both cartilaginous and soft tissues can be analyzed non-invasively, quickly, and accurately. The aim of this study is to provide a detailed anatomical description of the normal banded houndshark (Triakis scyllium) using computed tomography (CT) and magnetic resonance imaging (MRI) along with cryosection images. Three banded houndsharks were scanned using a 64-detector row spiral CT scanner and a 3 T MRI scanner. All images were digitally stored and assessed using open-source Digital Imaging and Communications in Medicine viewer software in the transverse, sagittal, and dorsal dimensions. The banded houndshark cadavers were then cryosectioned at approximately 1-cm intervals. Corresponding transverse cryosection images were chosen to identify the best anatomical correlations for transverse CT and MRI images. The resulting images provided excellent detail of the major anatomical structures of the banded houndshark. The illustrations in the present study could be considered as a useful reference for interpretation of normal and pathological imaging studies of sharks.

scholarly journals Comparison of the different voxel sizes in the estimation of peri-implant fenestration defects using cone beam computed tomography: an ex vivo study

2020 ◽  
Vol 6 (1) ◽  
Author(s):  
Mehmet Hakan Kurt ◽  
Nilsun Bağış ◽  
Cengiz Evli ◽  
Cemal Atakan ◽  
Kaan Orhan
Keyword(s):  
Computed Tomography ◽  
Cone Beam Computed Tomography ◽  
Ex Vivo ◽  
Statistical Significance ◽  
Area Under The Curve ◽  
Titanium Implant ◽  
Bone Defects ◽  
Titanium Implants ◽  
Cone Beam ◽  
Voxel Size

Abstract Background To examine the influence of voxel sizes to detect of peri-implant fenestration defects on cone beam computed tomography (CBCT) images. Materials and methods This study performed with three sheep heads both maxilla and mandible and two types of dental implant type 1 zirconium implant (Zr40) (n = 6) and type 2 titanium implant (Ti22) (n = 10). A total of 14 peri-implant fenestrations (8 buccal surfaces, 6 palatal/lingual surface) were created while 18 surfaces (8 buccal, 10 palatal/lingual) were free of fenestrations. Three observers have evaluated the images of fenestration at each site. Images obtained with 0.75 mm3, 0.100 mm3, 0.150 mm3, 0.200 mm3, and 0.400 mm3 voxel sizes. For intra- and inter-observer agreements for each voxel size, Kappa coefficients were calculated. Results Intra- and inter-observer kappa values were the highest for 0.150 mm3, and the lowest in 0.75 mm3 and 0.400 mm3 voxel sizes for all types of implants. The highest area under the curve (AUC) values were found higher for the scan mode of 0.150 mm3, whereas lower AUC values were found for the voxel size for 0.400 mm3. Titanium implants had higher AUC values than zirconium with the statistical significance for all voxel sizes (p ≤ 0.05). Conclusion A voxel size of 0.150 mm3 can be used to detect peri-implant fenestration bone defects. CBCT is the most reliable diagnostic tool for peri-implant fenestration bone defects.

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