Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: The heart is normal size . The hilar are mildly prominent . The mediastinal contours are unremarkable . There is no pneumothorax or pleural effusion . The lungs are well expanded . Subtle nodularity at the lung bases correspondS to findings on recent CT . There is no obvious radiographic correlate to the opacities in the upper lobes , which may have improved . Pulmonary vascularity is within normal limits . The upper abdomen is unremarkable .
    OUTPUT:
    
Severe atypical pneumonia , may be improving .