What is pulmonary angiography?

What is pulmonary angiography?
Pulmonary angiography is a procedure that uses a special dye (contrast material) and x-rays to see how blood flows through the lungs.
Angiography is an imaging test that uses x-rays and a special dye to see inside the arteries. Arteries are blood vessels that carry blood away from the heart.

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

Pulmonary angiography may also be used to help your doctor diagnose:
- AV malformations of the lung
- Congenital (present from bith) narrowing of the pulmonary vessels
- Pulmonary artery aneurysms
- Pulmonary hypertension - high blood pressure in the arteries of the lungs

How the Test is Performed
This test is done in a special unit of a hospital. You will be asked to lie on an x-ray table.
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 inserts a needle or makes a small cut in a vein in the area that has been cleaned, and inserts a catheter.
- The catheter is placed through the vein and carefully moved up into and through the right-sided 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 is injected into the catheter. X-ray images are taken to see how the dye moves through the lungs' arteries. The dye helps detect any blockages to blood flow.

Your pulse, blood pressure, and breathing are monitored during the procedure. Electrocardiogram (ECG) leads are taped to your arms and legs to monitor your heart.

After the x-rays are taken, the needle and catheter are removed.
Pressure is immediately applied to the puncture site for 20-45 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 6 hours after the procedure.
Rarely, this test can be used to deliver medications to the lungs when a blood clot has been found.

Considerations
CT (computed tomography) angiography of the chest has largely replaced this test.

Watch video:
Pulmonary Angiography of a PE Model AP
References:
http://www.hopkinsmedicine.org/healthlibrary/test_procedures/pulmonary/pulmonary_angiogram_92,P07758/
http://en.wikipedia.org/wiki/Pulmonary_angiography
http://www.webmd.com/lung/angiogram-of-the-lung
Image: pulmonary MR angiography via Wikimedia Commons