Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: A portable upright frontal chest radiograph demonstrates a normal cardiomediastinal silhouette and well - aerated lungs without pleural effusion or pneumothorax . Mildly increased opacity in the right lower lung could represent atelectasis , but infection can not be excluded in the right clinical setting . The visualized upper abdomen is unremarkable .
    OUTPUT:
    
Mildly increased opacity in the right lower lung could represent atelectasis , but infection can not be excluded in the right clinical setting .