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High-resolution CT image showing ground-glass opacities in the periphery of both lungs in a patient with COVID-19 (red arrows). The adjacent normal lung tissue with lower attenuation appears as darker areas. Ground-glass opacity (GGO) is a finding seen on chest x-ray (radiograph) or computed tomography (CT) imaging of the lungs.
A lung cavity or pulmonary cavity is an abnormal, thick-walled, air-filled space within the lung. [1] ... seen as a lucency or low-attenuation area, within [a] ...
In physics, attenuation (in some contexts, extinction) is the gradual loss of flux intensity through a medium.For instance, dark glasses attenuate sunlight, lead attenuates X-rays, and water and air attenuate both light and sound at variable attenuation rates.
Then oxyhemoglobin and deoxyhemoglobin will have similar contributions to the total absorption (black) and the effective attenuation (magenta) coefficient spectra, as shown in Figure 6 (b). Figure 7: : Effective penetration depth in breast tissue (StO2 ≈ 70%). Effective attenuation coefficient: λ min = 730 nm; NIR window = (626–1316) nm.
The Hounsfield unit (HU) scale is a linear transformation of the original linear attenuation coefficient measurement into one in which the radiodensity of distilled water at standard pressure and temperature is defined as 0 Hounsfield units (HU), while the radiodensity of air at STP is defined as −1000 HU.
A lung nodule or pulmonary nodule is a relatively small focal density in the lung. A solitary pulmonary nodule (SPN) or coin lesion, [1] is a mass in the lung smaller than three centimeters in diameter. A pulmonary micronodule has a diameter of less than three millimetres. [2] There may also be multiple nodules.
The attenuation coefficient of a volume, denoted μ, is defined as [6] =, where Φ e is the radiant flux;; z is the path length of the beam.; Note that for an attenuation coefficient which does not vary with z, this equation is solved along a line from =0 to as:
A pleural effusion is accumulation of excessive fluid in the pleural space, the potential space that surrounds each lung.Under normal conditions, pleural fluid is secreted by the parietal pleural capillaries at a rate of 0.6 millilitre per kilogram weight per hour, and is cleared by lymphatic absorption leaving behind only 5–15 millilitres of fluid, which helps to maintain a functional ...