Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: AP upright portable chest radiograph is obtained . As seen on prior CT , patient is known to have interstitial fibrosis with subpleural fibrosis likely accounting for the increased reticular opacities seen peripherally on the chest radiograph . There is atelectasis versus scarring at the left lung base which appears stable from prior exam . There is no definite sign of a superimposed pneumonia . No pleural effusion is seen . No pneumothorax . Cardiomediastinum appears stable . Bony structures appear intact . Relative deformity of the right distal clavicle likely reflects an old injury .
    OUTPUT:
    
Coarsened subpleural markings c / w known interstitial lung disease with scarring versus atelectasis in the left lower lobe . No signs of pneumonia or CHF .