A<unk>  (CTPA) is a medical diagnostic test that employs computed tomography (CT)<unk> hy to obtain an image of the<unk>  arteries. Its main use is to diagnose<unk>  embolism (PE). It is a preferred choice of imaging in the diagnosis of PE due to its minimally invasive nature for the patient, whose only requirement for the scan is an intravenous line. Modern MDCT (multi-detector CT) scanners are able to deliver images of sufficient resolution within a short time period, such that CTPA has now supplanted previous methods of testing, such as direct<unk> <unk> hy, as the gold standard for diagnosis of<unk>  embolism. The patient receives an intravenous injection of an iodine-containing contrast agent at a high-rate using an injector pump. Images are acquired with the maximum intensity of radio-opaque contrast in the<unk>  arteries. This can be done using bolus tracking. A normal CTPA scan will show the contrast filling the<unk>  vessels, appearing as bright white. Any mass filling defects, such as an embolus, will appear dark in place of the contrast, filling/blocking the space where blood should be flowing into the lungs.
CT pulmonary angiogram
Pulmonary angiography
Fractional flow reserve
Carbon dioxide angiography
Intravascular imaging
Lung biopsy
Coronary catheterization
Thoracoscopy