CT pulmonary angiogram

CT pulmonary angiogram (CTPA) is a medical diagnostic test that employs computed tomography to obtain an image of the pulmonary arteries. Its main use is to diagnosepulmonary embolism (PE).^[1] 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, that CTPA has now supplanted previous methods of testing, such as isotope scanning or direct pulmonary angiography, as the gold standardfor diagnosis of pulmonary embolism.

The patient receives an intravenous injection of an iodine-containing contrast agent at a high-rate using a injector pump. Images are acquired with the maximum intensity of radio-opaque contrast in the pulmonary arteries. This can be done using bolus tracking.

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.

Contents   [hide]  1 Diagnostic use 2 Contraindications 3 Acquisition 4 Interpretation 5 References