Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: PA and lateral views of the chest provided . Lung volumes are low . There is mild left basal opacity which is more compatible with atelectasis though difficult to exclude a subtle pneumonia . Otherwise lungs are clear . No large effusion or pneumothorax . Cardiomediastinal silhouette is unchanged . Bony structures appear intact .
    OUTPUT:
    
Mild left basal opacity which could represent atelectasis , though difficult to exclude pneumonia in the correct clinical setting .