Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Lung volumes are low , accentuating the cardiomediastinal contours . The heart size is top - normal . The mediastinal and hilar contours are unremarkable . There is no pneumothorax or pleural effusion . A focal opacity at the right lung base medially may represent atelectasis or aspiration .
    OUTPUT:
    
Low lung volumes with atelectasis or aspiration at the right lung base . Top normal heart size .