Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Portable AP chest radiograph is somewhat limited by rotation to the left . However , it does ___ lung volumes with mild pulmonary interstitial edema . There is no large pleural effusion or pneumothorax . Heart size is difficult to ascertain .
    OUTPUT:
    
Mild interstitial edema . Low lung volumes limit study and PA / lateral radiographs are recommended .