A pulmonary angiography is is a procedure that uses a special dye (contrast material) and x-rays to see how blood flows through the lungs.

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.

Before the test starts, you will be given a mild sedative to help you relax.

An area of your body, usually the arm or groin, is cleaned and numbed with a local numbing medicine (anesthetic). The radiologist makes a small surgical cut in an artery in the area that has been cleaned, and inserts a thin hollow tube called a catheter. The catheter is placed through the artery and carefully moved up into and through the heart chambers and into the pulmonary artery, which leads to the lungs.

The doctor can see live x-ray images of the area on a TV-like monitor, and uses them as a guide.

Once the catheter is in place, dye (contrast material) is injected into catheter. X-ray images are taken to see how the dye moves through the lung arteries. The dye helps highlight any blockages in blood flow.

The catheter is occasionally flushed with saline solution containing a drug called heparin to help keep blood in the tube from clotting.

Your 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After the x-rays are taken, the needle and catheter are withdrawn.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 to the puncture site for 10-15 minutes to stop the bleeding. After that time the area is checked and a tight bandage is applied. The leg should be kept straight for 12 hours after the procedure.

You should not eat or drink anything for 4 - 8 hours before the test.

You will be asked to wear a hospital gown and sign a consent form for the procedure. Jewelry should be removed from the area being imaged.

Tell your health care provider:

• If you are pregnant
• If you have ever had any allergic reactions to x-ray contrast material or iodine substances
• If you are allergic to any medications
• Which medications you are taking (including any herbal preparations)
• If you have ever had any bleeding problems

The x-ray table is hard and cold, but you may ask for a blanket or pillow. You may feel a brief sting when the numbing medicine is given and a brief, sharp, stick as the catheter is inserted.

You may feel some pressure as the catheter moves up into the lungs. The contrast dye can cause a feeling of warmth and flushing. This is normal and usually goes away in a few seconds.

You may have some tenderness and bruising at the site of the injection after the test.

The test is used to detect blood clots and other blockages in the blood flow in the lung (pulmonary embolism).

The x-ray will show normal structures for the age of the patient.

Abnormal results may be due to:

• Blood clot in the lungs
• Narrowed blood vessel
• Primary pulmonary hypertension
• Pulmonary embolism
• Tumor

Occasionally abnormal cardiac rhythm can develop during the procedure. The doctors will monitor your heart and can treat any abnormal rhythms that develop.

Other risks include:

• Allergic reaction to the contrast dye
• Blood vessel damage
• Blood clot traveling to the lungs, causing an embolism
• Excessive bleeding or blood clot, which can reduce 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.

Rubens MB, Dalal P. Pulmonary Circulation and Pulmonary Thromboembolism. In: Grainger RC, Allison D, Adam, Dixon AK, eds. Diagnostic Radiology: A Textbook of Medical Imaging. 5th ed. New York, NY: Churchill Livingstone; 2008:chap 26.