Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Portable AP upright chest radiograph was obtained . Low lung volumes limit evaluation . Heart size appears top normal and stable . Left mid lung linear density is likely atelectasis . No definite signs of pneumonia or overt CHF . No large pleural effusions or pneumothorax . There is an old left rib cage deformity along the left fifth posterior arch .
    OUTPUT:
    
Low lung volumes , mild cardiomegaly . Otherwise unremarkable .