Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Cardiac silhouette size is normal . The mediastinal and hilar contours are unremarkable . Pulmonary vasculature is not engorged . Patchy opacities are noted in the lung bases , without focal consolidation , pleural effusion or pneumothorax . Mild degenerative changes are present within the thoracic spine .
    OUTPUT:
    
Patchy opacities in the lung bases are nonspecific and likely reflect atelectasis . Infection , however , can not be excluded in the correct clinical setting .