For emergencies concerning the heart and blood vessels angiography is often used to get a clear picture of the problem. CT pulmonary angiography is a quick and easy test: dye called contrast media is injected via a small needle in a vein in the arm during a CT scan. The dye shows up clearly in the bloodstream in the resulting x-ray image (called an angiogram) which helps radiologists to investigate the problem area.

This angiogram shows a clot in the main pulmonary (lung) arteries (arrows) of this patient, who had just flown long haul. The diagnosis of a blood clot in the lung vessels can be made straight away and blood thinning treatment can then start immediately.

Blocked artery in lung (pulmonary embolism)