Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Lung volumes are low , with crowding of bronchovascular markings . Streaky retrocardiac opacity is most compatible with atelectasis . There are no pleural effusions or pneumothorax . Biapical pleural parenchymal scarring is noted . Heart size is top normal to mildly enlarged . The aorta is tortuous and calcified . There are severe degenerative changes at the right glenohumeral joint , with bone - on - bone contact , subchondral sclerosis and cyst formation . Total left glenohumeral prosthesis is also present , partially imaged .
    OUTPUT:
    
Left lower lobe atelectasis .