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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 ...
Computed tomography angiography (also called CT angiography or CTA) is a computed tomography technique used for angiography—the visualization of arteries and veins—throughout the human body. Using contrast injected into the blood vessels, images are created to look for blockages, aneurysms (dilations of walls), dissections (tearing of walls ...
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.
Pulmonary angiography is useful as the confirmation test where the non-invasive imaging such as CT pulmonary angiography is inconclusive on determining the presence of pulmonary embolism. [1] The accuracy of pulmonary angiography may be higher than clinical examination, arterial blood gas results, and ventilation/perfusion scan. [2]
CT angiography is a contrast CT taken at the location and corresponding phase of the blood vessels of interest, in order to detect vascular diseases. For example, an abdominal aortic angiography is taken in the arterial phase in the abdominal level, and is useful to detect for example aortic dissection. [10]
The two scanners are located in the same machine, but they do not perform scans at the same time. A CT scan is typically done first, followed by a PET scan. [22] For cardiac scans, combining CT cardiac data with PET metabolic or perfusion data from PET/CT machines may be of clinical value.
A helical CT beam trajectory is characterized by its pitch, which is equal to the table feed distance along the scan range over one gantry rotation divided by the section collimation. [9] When pitch is greater than 1, the radiation dose for a given axial field of view (FOV) is decreased compared to conventional CT. At high pitches there is ...
Digital subtraction angiography (DSA) is a fluoroscopy technique used in interventional radiology to clearly visualize blood vessels in a bony or dense soft tissue environment. 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 ...