Blood Clot Diagnosis
This depends upon age, health, and underlying medical conditions, as well as the cause of the PE.
One-third to two-thirds.
The risk varies depending on the location of the clot. The risk for a PE increases the higher up in the leg the DVT occurs. For example, a calf DVT has a lower risk of breaking off and becoming a PE than a clot behind the knee or one in the groin or pelvic veins. Essentially, the larger the vein with the clot, the greater the risk of developing a PE.
A DVT is often the source of a clot that travels to the lung arteries and becomes a PE.
If a VQ scan does not identify a clot, but one is still suspected, a pulmonary angiogram is performed. A catheter is threaded through a vein in the groin, passed through the heart, and into the pulmonary artery. Contrast dye is then injected and X-rays are taken to monitor the blood flow in the lung. The angiogram will give a definite diagnosis as to the presence of a clot. Occasionally, an echocardiogram will show abnormalities in heart function, particularly in the right ventricle, as it meets resistance in pumping blood into the lungs. Learn more about PE diagnosis.
Most often, ultrasound is used to diagnose blood clots in the leg veins. This is a non-invasive test. If the results are not definitive, then venography (an invasive test using contrast dye) or MRI (magnetic resonance imaging) may be used. Learn more about DVT diagnosis.