Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Lung volumes remain low . Chronic interstitial opacities are again noted bilaterally , most pronounced within the periphery and lung bases , previously thought to reflect NSIP . Moderate cardiomegaly is unchanged . The mediastinal and hilar contours are unchanged . Crowding of bronchovascular structures is likely due to the presence of low lung volumes without overt pulmonary edema . Slightly increased opacification at the lung bases may reflect superimposed atelectasis . No large pleural effusion or pneumothorax is present . Left humeral prosthesis is incompletely imaged .
    OUTPUT:
    
Low lung volumes with chronic interstitial opacities compatible with previously characterized NSIP . Slightly increased patchy opacities in the lung bases may reflect superimposed atelectasis , however infection is difficult to exclude .