Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: AP upright portable chest radiograph is obtained . Lung volumes are low . There is no focal consolidation , effusion , or pneumothorax . No frank CHF , though mild interstitial edema can not be excluded . Heart and mediastinal contours appear within normal limits . The bony structures appear grossly intact .
    OUTPUT:
    
No overt abnormality on this limited study .