A pulmonary embolus (blood clot in the lung) within a pulmonary artery. The artery is white (because of high-density intravenous contrast), and the PE (arrow) is a dark glob within the artery.
PA = main Pulmonary Artery
L = Lungs (appear dark compared to the rest of the body because the air in lungs allows the xrays to pass through easily)
A = Aorta (the major artery leaving the heart)
Note: Images are shown for illustrative purposes. Do not attempt to draw conclusions or make diagnoses by
comparing these images to other medical images, particularly your own. Only qualified physicians should interpret images;
the radiologist is the physician expert trained in