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Low-dose high-resolution (1.25 mm) chest CT. HRCT is performed using a conventional CT scanner. However, imaging parameters are chosen so as to maximize spatial resolution: [1] a narrow slice width is used (usually 1–2 mm), a high spatial resolution image reconstruction algorithm is used, field of view is minimized, so as to minimize the size of each pixel, and other scan factors (e.g. focal ...
Contrast agents are sometimes used in CT scans of the chest to accentuate or enhance the differences in radiopacity between vascularized and less vascularized structures, but a standard chest CT scan is usually non-contrasted (i.e. "plain") and relies on different algorithms to produce various series of digitalized images known as view or "window".
A computed tomography scan (CT scan), formerly called computed axial tomography scan (CAT scan), is a medical imaging technique used to obtain detailed internal images of the body. [2] The personnel that perform CT scans are called radiographers or radiology technologists.
Opting for an alternative type of scan without contrast might result in a 10 to 20 percent reduction in diagnostic accuracy, he said. Other sources of the dye are limited, however.
The differential for diffuse shadowing is very broad and can defeat even the most experienced radiologist. It is seldom possible to reach a diagnosis on the basis of the chest radiograph alone: high-resolution CT of the chest is usually required and sometimes a lung biopsy. The following features should be noted:
Ground-glass opacity is most often used to describe findings in high-resolution CT imaging of the thorax, although it is also used when describing chest radiographs. In CT, the term refers to one or multiple areas of increased attenuation (density) without concealment of the pulmonary vasculature. This appears more grey, as opposed to the ...
In conventional CT machines, an X-ray tube and detector are physically rotated behind a circular shroud (see the image above right). An alternative, short lived design, known as electron beam tomography (EBT), used electromagnetic deflection of an electron beam within a very large conical X-ray tube and a stationary array of detectors to achieve very high temporal resolution, for imaging of ...
Two forms of radiographic images are in use in medical imaging. Projection radiography and fluoroscopy, with the latter being useful for catheter guidance. These 2D techniques are still in wide use despite the advance of 3D tomography due to the low cost, high resolution, and depending on the application, lower radiation dosages with 2D technique.