title: Symmetrical perfusion defects without pulmonary embolism.
mesh_terms: D000328:Adult; D000792:Angiography; D005189:False Positive Reactions; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011655:Pulmonary Embolism / Q000175:diagnosis* / Q000000981:diagnostic imaging; D011877:Radionuclide Imaging; D012709:Serum Albumin; D013667:Technetium; D013668:Technetium Tc 99m Aggregated Albumin; D014692:Ventilation-Perfusion Ratio; D014980:Xenon Radioisotopes
chemical_list: D012709:Serum Albumin; D013668:Technetium Tc 99m Aggregated Albumin; D014980:Xenon Radioisotopes; D013667:Technetium