Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: PA and lateral chest radiograph demonstrates a subtle opacity involving the left lower lobe . Remaining lungs are clear . Cardiomediastinal and hilar contours are within normal limits . Imaged osseous structures and upper abdomen are without an acute abnormality .
    OUTPUT:
    
Subtle opacification in the left lower lobe which may represent infectious process . Follow up to resolution is recommended if the patient 's symptoms do not improve .