Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: The lung volumes are decreased . The heart size is mildly enlarged . The aorta is tortuous . Pulmonary vascularity and hilar contours are within normal limits . There are increased interstitial markings most pronounced at the lung bases , which could be reflective of a chronic interstitial lung disease , though a superimposed infectious process in the left lung base is difficult to exclude . No focal consolidation , pleural effusion or pneumothorax is definitively noted . Minimal degenerative changes are noted in the thoracic spine .
    OUTPUT:
    
Increased interstitial markings most pronounced at the lung bases , which could reflect an underlying chronic interstitial lung disease . A superimposed infectious process in the left lung base is difficult to exclude .