Pulmonary angiography

Many patients do not have a pulmonary angiography test carried out but it can be used in adults when the results of a ventilation-perfusion scan are inconclusive. It is the best test for the diagnosis of possible blood clots and it is therefore used to confirm or exclude the presence of blood clots in the lungs.

The patient is attached to an ECG (electrocardiogram) machine and lies on an X-ray table while a long, narrow, flexible tube (catheter) is inserted through a needle placed in a vein in the groin. While the operator watches a TV monitor, the catheter is advanced through the chambers of the heart and into the pulmonary artery. A dye is then injected into the arteries of the lung through the catheter and a series of X-ray films are taken. This dye allows the arteries to be more easily visible. Aided by the dye, the pulmonary angiography produces a series of highly detailed X-ray images (known as “angiograms”) of the pulmonary artery and its smaller branches. The radiologist then looks at the angiograms for any problems, for example to see when blood clots are present or for evidence of other lung problems.

A small minority of patients who have the pulmonary angiography test carried out are allergic to the liquid dye due to the iodine content. Anyone who has previously experienced such reactions should mention this to the doctor. Pregnant women should enquire about the risks of the X-ray screening harming their baby. The risk of X-rays being harmful to a patient is very small and modern X-ray machines are designed to take high quality pictures using a minimal radiation dose.