This test is done in a hospital. You will be asked to lie on an X-ray table. Electrocardiogram (ECG) leads are taped to your arms and legs to monitor the electrical impulses of the heart.

The area where the contrast medium will be introduced is shaved and cleansed. The site is usually a vein in the groin. A local anesthetic is given, the vein is punctured, and a needle is inserted into the vein. A catheter is inserted through the needle, into the vein, through the chambers of the heart, and into the pulmonary artery, which leads to the lungs. This procedure is monitored by a fluoroscope (a type of X-ray that projects the images on a TV monitor).

The contrast medium is then injected into the lung arteries through the catheter, and the X-ray pictures are taken. The catheter is flushed periodically with a saline solution containing heparin, which will keep blood in the catheter from clotting. The pulse, blood pressure, and breathing are monitored during the procedure.

After the X-rays are taken, the needle and catheter are withdrawn. Pressure is immediately applied on the leg at the site of insertion for 10 to 15 minutes to stop the bleeding. After that time the area is checked and a tight bandage is applied.

The health care provider may advise you to keep the leg straight for an additional 12 hours after the procedure.

You will be restricted from food or fluid 4 to 8 hours before the procedure.

Inform the health care provider if you are pregnant and if you have ever had any bleeding problems. Report any allergic reactions to X-ray contrast material or any iodine substance and any other allergic reactions you have.

You must sign a consent form. You will be given a gown to wear, and you need to remove any jewelry. You may be given a sedative or a pain pill before the procedure.

Infants and children:
The physical and psychological preparation you can provide for this or any test or procedure depends on your child's age, interests, previous experience, and level of trust. For specific information regarding how you can prepare your child, see the following topics as they correspond to your child's age:

• Infant test or procedure preparation (birth to 1 year)
• Toddler test or procedure preparation (1 to 3 years)
• Preschooler test or procedure preparation (3 to 6 years)
• Schoolage test or procedure preparation (6 to 12 years)
• Adolescent test or procedure preparation (12 to 18 years)

The test may show a blockage in the vessels that may be caused by a blood clot, narrowed blood vessels, or blood vessels that are displaced due to a tumor.

Additional conditions under which the test may be performed:

• Primary pulmonary hypertension
• Pulmonary embolus

There is the possibility of significant risk associated with pulmonary angiography. There is a possibility of a reaction to the contrast medium. There is some risk of the catheter damaging the vein and a blood clot traveling to the lungs and causing an embolism. A clot or excessive bleeding at the puncture site may result in a partial blockage of the blood flow to the leg.

There is low radiation exposure. X-rays are monitored and regulated to provide the minimum amount of radiation exposure needed to produce the image. Most experts feel that the risk is low compared with the benefits.

Pregnant women and children are more sensitive to the risks of X-rays.