What does mild linear atelectasis in the bilateral lower lobes and right middle lobes mean?

Atelectasis: Atelectasis is a condition in which one or more areas of your lungs collapse or don't inflate properly. If only a small area or a few small areas of lung are affected, you may have no signs or symptoms. If a large area or several large areas of lung are affected, they may not be able to deliver enough oxygen to your blood. This can cause symptoms and complications.