SUMMARY 4- Pulmonary vessels and emboli

-Normal large pulmonary vessels are present in the inner third of the lung on CXR, with tapering branches visible in the middle third, and no normal vessels in the outer third

-Pulmonary emboli rarely show any abnormality on CXR, but occasionally can result in pulmonary infarction, which presents as peripheral wedge-shaped opacity

-Hallmarks of embolic disease (such as after prolonged sitting)-filling defects in pulmonary vessels on CT with contrast

In order to visualize pulmonary emboli, very dense contrast is needed within central pulmonary arteries, which requires careful timing of scans relative to IV contrast administration. Without adequate opacification, emboli will not be visible.

With VASCULAR DISEASE, the density of the abnormality is within vessels, that are similar in density, so they are NOT visible on CXR

NORMAL

VASCULAR DISEASE