Tc-99m MAA lung perfusion scintigraphy performed before and after pulmonary embolectomy for saddle-type pulmonary embolism.

A 58-year-old man had shortness of breath, hypotension, and decreased partial pressure of oxygen (PO2) on the eighteenth day after undergoing craniotomy for a meningioma. Tc-99m MAA pulmonary perfusion scintigraphy showed little perfusion to the right lung and left lower lung and multiple perfusion defects in the left upper lung. Although the results of concurrent chest radiography were negative for pulmonary infiltrates, pulmonary angiography demonstrated a saddle-type embolism. The patient underwent emergency pulmonary artery embolectomy to remove blood clots and organized thromboemboli from the main pulmonary artery and the right and left pulmonary arteries. The patient's postoperative course was uneventful, and a second Tc-99m MAA lung perfusion scan demonstrated marked improvement in lung perfusion.