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Coronary CT angiography (CTA or CCTA) is the use of computed tomography (CT) angiography to assess the coronary arteries of the heart.The patient receives an intravenous injection of radiocontrast and then the heart is scanned using a high speed CT scanner, allowing physicians to assess the extent of occlusion in the coronary arteries, usually in order to diagnose coronary artery disease.
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 ...
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 ...
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.
Selective pulmonary angiogram revealing significant thrombus (labelled A) causing a central obstruction in the left main pulmonary artery. Pulmonary angiography (or pulmonary arteriography,conventional pulmonary angiography, selective pulmonary angiography) is a medical fluoroscopic procedure used to visualize the pulmonary arteries and much less frequently, the pulmonary veins.
A typical coronary CT calcium scan is done without the use of radiocontrast agent but it can also be performed using contrast-enhanced images as well, such as in coronary CT angiography. [4] The exam is best performed with cardiac gating to eliminate motion but can also be estimated in the presence of motion.
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".
Images are produced using contrast medium by subtracting a "pre-contrast image" or mask from subsequent images, once the contrast medium has been introduced into a structure. Hence the term "digital subtraction angiography. [1] [2] Subtraction angiography was first described in 1935 and in English sources in 1962 as a manual technique. Digital ...