CT Perspective of Normal Cardiovascular Anatomy
Paul Schoenhagen, Frank Dong in Cardiac CT Made Easy, 2023
Volume-rendered (VR) techniques employ advanced 3-D image processing algorithms with semitransparent visualization of superficial and deep contours. Each voxel is assigned a value for opacity according to its CT number, such that lower-intensity tissues are more transparent while higher-intensity tissues are more opaque. Therefore, the more opaque tissue is visible through translucent tissue, creating depth perception. VR images allow the demonstration of complex anatomy and appreciation of the spatial relationship between visualized structures. Levels of opacity can be varied to alter the display of data as needed. In addition, the VR data can be viewed at arbitrary angles, including the standard views of conventional coronary angiography (right anterior oblique/ left anterior oblique [RAO/LAO], cranial/caudal). Colour coding can also be used to enhance further the 3-D appearance.
Conventional film processing
Damian Tolan, Rachel Hyland, Christopher Taylor, Arnold Cowen in Get Through, 2020
True.True – where the opacity is defined as the ratio of light incident to that transmitted by the film. Photographic density is also known as optical density and film density.True – on this basis the term opacity is the reciprocal of transmission.True – as log10 100 = 2, the ratio of incident to transmitted light is 100 : 1. In simple terms, for every 100 photons incident on the film, only one photon, or 1% (0.01) is transmitted.False – a photographic density of 1.0 equates to 10% light transmission and a density of 2.0 equates to 1% transmission. Therefore a film with a photographic density of 2.0 will transmit one tenth of the light that a film with a photographic density of 1.0 will transmit.
Assembly of a Technological Vision for X-Ray Contrast Agents
Christoph de Haën in X-Ray Contrast Agent Technology, 2019
The press reports sufficed to attract to the exploration of X-rays numerous investigators. They came from all sectors of the educated class, representing universities, high schools, private individuals and their associations, nonacademic public institutions, and industry. Most investigators let the quasi obligatory initial hand radiograph be followed by radiographs of diverse objects, without systematic objective. But already within a few weeks after the news on X-rays had broken, radiographs of medical interest were produced. Bone pathologies were detected and imaging of foreign objects in tissues facilitated their surgical removal. Much attention was given to the study of the opacity of materials, and this is also the most relevant aspect for the present endeavor. The choice of the materials, and the type of explanation for the observations offered, reflected the knowledge culture of the investigators. Physicists, like Röntgen, addressed the role of bulk physical properties of materials used in their laboratories irrespective of their chemical composition (glasses, brass, ebony, lead, steel, water, etc.). Chemists examined pure elements in series related by the periodic chart and pure chemical compounds containing these, including salts as solids and in solution. Pharmacists concentrated on therapeutic products and their elemental composition. Military physicians explored wound dressings, disinfecting agents, and plaster casts.
Clinical features and high-resolution chest computerized tomography findings of children infected by the B.1.617.2 variant of coronavirus disease 2019
Published in Annals of Medicine, 2022
Chuanjun Xu, Mengya Ma, Yongxiang Yi, Changhua Yi, Hui Dai
There were 9 cases of CT images in the early stage (1.9 ± 0.9 days), 10 cases in the intermediate stage (4.9 ± 1.0 days) and 20 cases in the late stage (13.5 ± 4.7 days). The different opacity characteristics are shown in Figure 3. In the early stage, three cases (33%) showed GGO, one case (11%) showed consolidation and one case (11%) showed GGO and consolidation. In the intermediate stage, two cases (20%) showed GGO, three cases (30%) showed consolidation and two cases (20%) showed GGO and consolidation. In the late stage, eight cases (40%) showed GGO, three cases (15%) showed consolidation and four cases (20%) showed GGO and consolidation. Ten of 14 (71%) consolidations were accompanied by halo signs. The frequencies of opacity characteristics are shown in Figure 4. Some CT signs, such as bronchial mucus plugs (one case), localized thickening of the interlobular pleura (one case), limited emphysema distal to the lesion (two cases), and pulmonary fibrosis (one case), were seen in fewer children. CT of the chest did not show pleural effusion or lymph node enlargement.
Celiac disease and idiopathic pulmonary hemosiderosis: a literature review of the Lane–Hamilton syndrome
Published in Postgraduate Medicine, 2022
Stavros Tryfon, Efthymia Papadopoulou, Georgios Psarros, Michael Agrafiotis, Maria Saroglou
Diffuse alveolar hemorrhage demonstrates patchy or diffuse ground-glass opacities, and is sometimes accompanied by consolidation or ill-defined centrilobular opacities. There are different patterns on high-resolution CT scan depending on the hemorrhage onset [45]. In the phase of acute hemorrhage, lobular or lobar areas of ground-glass opacity to consolidation predominate. In such cases, ground-glass opacity is generated by subtotal alveolar filling with blood and is accompanied by apparent prominence of the segmental and subsegmental bronchi, which has been referred to as the ‘dark bronchus’ sign. Ground-glass opacity is defined as a nonspecific term referring to ‘the presence on high-resolution CT of a hazy increase in lung opacity not associated with obscuration of underlying vessels’ [46], and implies a long list of differential diagnosis, occupying either alveoli or interstitium, or both. Therefore, in the interpretation of cases with ground-glass opacities, relevant clinical information is often crucial.
Regenerative responses of rabbit corneal endothelial cells to stimulation by fibroblast growth factor 1 (FGF1) derivatives, TTHX1001 and TTHX1114
Published in Growth Factors, 2021
Jessica Weant, David D. Eveleth, Amuthakannan Subramaniam, Jennifer Jenkins-Eveleth, Michael Blaber, Ling Li, David M. Ornitz, Asaf Alimardanov, Trevor Broadt, Hui Dong, Vinay Vyas, Xiaoyi Yang, Ralph A. Bradshaw
Treatment with TTHX1114 also improved clearing of corneal opacity from involvement of the entire thickness of the stroma (3+) following injury to some loss of transparency with only the epithelium and/or involvement of the anterior half of the stroma (1+) by Day 14 (Figure 6). In contrast, corneal clearing in contralateral control eyes that received only vehicle progressed to some loss of transparency with cloudiness that extended past the anterior half of the stroma (2+) by Day 14. There was significant acceleration of improvement in opacity compared to contralateral vehicle control eyes at Day 5 for the 1,000 ng/eye and 5,000 ng/eye doses of TTHX1114 and at Day 7 and 14 for all doses. There was no clear differentiation of doses between 100 and 5,000 ng/eye, suggesting that all doses are at the top of the dose response curve. Both TTHX1001 and TTHX1114 were equally effective in the corneal clearing effects.
Related Knowledge Centers
- Absorption
- Carbon Black
- Refraction
- Ultraviolet
- Radiative Transfer
- Radiation Protection
- Cesia
- Mathematical Descriptions of Opacity
- Reflection
- Scattering