Diagnosing Pulmonary Embolism
A duplex ultrasound is the most common test used to make a deep vein thrombosis diagnosis. This test uses sound waves to evaluate the flow of blood in your veins. This test involves the following steps:
- A gel is put on the skin of the leg
- A handheld device is placed on the leg and passed back and forth over the affected area
- This device sends sound waves from the leg to an ultrasound machine
- A computer then turns the sounds into a picture
- The picture is displayed on a TV screen, where your doctor can see the blood flow in your leg.
This is an indirect way to diagnose a source of pulmonary embolism.
Blood work is used to check for inherited disorders that cause clots. A blood test measures the amount of oxygen and carbon dioxide in the blood (arterial blood gas), because a pulmonary embolism may change the levels of oxygen and carbon dioxide in the blood.
Other tests used to make a pulmonary embolism diagnosis include:
- Ventilation/perfusion lung scan (V/Q scan)
- Pulmonary angiography
- Spiral computed tomography (CT) scan
- Magnetic resonance imaging (MRI)
Ventilation/Perfusion Lung Scan (V/Q Scan)
A V/Q scan is a test that uses a radioactive material to see how well air and blood are flowing to all areas of the lung.
A pulmonary angiography is an accurate, invasive test that is used to diagnose pulmonary embolism. A trained specialist will thread a flexible tube called a catheter through the groin or arm to the blood vessels in the lung. The specialist will then inject a dye to take a picture of the blood flow through the blood vessels in the lungs. This test is not available at all hospitals, and a trained specialist is required to perform this test.