What condition is pulmonary angiography primarily used to diagnose?

Pulmonary angiography is primarily used to diagnose pulmonary embolism, which is a blockage in one or more of the pulmonary arteries in the lungs typically caused by blood clots that travel to the lungs from the legs or other parts of the body. This procedure involves injecting a contrast dye into the pulmonary arteries and taking X-ray images to visualize the blood flow in the lungs. By allowing for direct observation of emboli, it helps confirm the presence of a blockage and is considered a definitive diagnostic tool for pulmonary emboli.

In contrast, heart failure is diagnosed through physical examination, echocardiograms, and other non-invasive tests rather than angiography. Interstitial lung disease involves issues with the lung tissue itself, which is typically evaluated with imaging techniques such as CT scans and pulmonary function tests, rather than angiography. Chronic obstructive pulmonary disease (COPD) is diagnosed through symptoms assessment, lung function tests, and imaging, but not specifically by pulmonary angiography, as it does not directly involve vascular interpretation of the lungs. Therefore, the use of pulmonary angiography aligns specifically with identifying pulmonary emboli.