Scans are only part of the puzzle. The ENT gave you a key piece of information. Fibrosis of the lungs is defined as scar tissue (a natural result of pneumonia). Scar lasts forever in the lungs I believe. In my experience the radiologists do a lot of speculation about what they encounter and leave it to the other doctors to interpret it. Their reports can be downright scary. They are being very cautious because of the stage.