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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 CT pulmonary angiogram, in this case showing pulmonary embolism of saddle-type, which becomes more radiolucent than the radiocontrast filled blood surrounding it (but it may be indistinguishable without radiocontrast). Contrast CT, or contrast-enhanced computed tomography (CECT), is X-ray computed tomography (CT) using radiocontrast.
State of the art modern CT scanners with a scan rate of up to 320 mm/s can acquire all the images within a 1-second X-ray exposure, avoiding the problems of respiratory motion, cardiac motion and contrast draining from the pulmonary circulation during the study. Even though the actual scan may be completed in 1 second or less, considerable ...
CT scanning can perform a virtual colonoscopy with greater accuracy and less discomfort for the patient than a traditional colonoscopy. [143] [144] Virtual colonography is far more accurate than a barium enema for detection of tumors and uses a lower radiation dose. [145] CT is a moderate-to-high radiation diagnostic technique.
Volume rendered CT scan of abdominal and pelvic blood vessels. CT angiography is a contrast CT where images are taken with a certain delay after injection of radiocontrast material. The contrast material is radiodense causing it to light up brightly within the blood vessels of interest. In order for the CT scanner to be able to scan the correct ...
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 ...
Ground-glass opacity (GGO) is a finding seen on chest x-ray (radiograph) or computed tomography (CT) imaging of the lungs. It is typically defined as an area of hazy opacification (x-ray) or increased attenuation (CT) due to air displacement by fluid, airway collapse, fibrosis , or a neoplastic process . [ 1 ]
Cardiac CT (CCT) is a modified form of the traditional chest CT due to the difficulty of imaging the complex, moving heart. [16] This is achieved through the use of thin slices and high-resolution scanning, as well as the addition of electrocardiogram (ECG) gating or triggering to capture a motion-free image.