Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: PA and lateral chest radiographs were obtained . The lungs are well expanded . There is a subtle interstitial abnormality in the left lower lobe . There is no focal consolidation , effusion , or pneumothorax . Cardiac and mediastinal contours are normal .
    OUTPUT:
    
Subtle interstitial abnormality in the left lower lobe which could represent infection or other non-specific process .