CT pulmonary angiogram

A CT pulmonary angiogram (CTPA) is a medical diagnostic test that employs <a href="/facts/Computed_tomography_angiography/3lsmfSWt">computed tomography (CT) angiography</a> to obtain an image of the <a href="/facts/Pulmonary_artery/86j5Jc7D">pulmonary arteries</a>. Its main use is to diagnose <a href="/facts/Pulmonary_embolism/LPjKCPba">pulmonary embolism</a> (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 <a href="/facts/Pulmonary_angiography/TJbhUezA">pulmonary angiography</a>, as the <a href="/facts/Gold_standard_(test)/Hbf0tb93">gold standard</a> for diagnosis of pulmonary embolism.
The patient receives an <a href="/facts/Intravenous/AwwuD3Nu">intravenous</a> injection of an iodine-containing <a href="/facts/Contrast_agent/uVoPWL7Q">contrast agent</a> at a high rate using an injector pump. Images are acquired with the maximum intensity of radio-opaque contrast in the pulmonary arteries. This can be done using <a href="/facts/Bolus_tracking/t9jG2qBc">bolus tracking</a>.
A normal CTPA scan will show the contrast filling the pulmonary 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 open-in-new

CT pulmonary angiogram