Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Heart size , mediastinal and hilar contours are within normal limits allowing for relatively low lung volumes . Lungs are grossly clear . Minimal blunting of left posterior costophrenic sulcus is present on lateral view . Pleural surfaces are otherwise unremarkable .
    OUTPUT:
    
Questionable small left pleural effusion vs . pleural thickening . Otherwise , unremarkable radiograph .