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Long term assessment of ventilation defects (A) Large (arrow) and small defect (small arrow) are shown at baseline. (B) The defects are unchanged in location and size (arrow) 38 days later. (C) The large defect is also unchanged at 412 days (arrow). The small defect (small arrow) has slightly decreased in size, and a new central defect (open arrow) has developed. Reprinted with permission from Radiology. 2009;250:567–75
