Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Cardiac silhouette size is mildly enlarged , unchanged . The aortic knob is calcified . Mediastinal and hilar contours are unchanged . Pulmonary vasculature is not engorged . Lung volumes are low with patchy opacities in the lung bases , more so on the right . No pleural effusion or pneumothorax is present . No acute osseous abnormalities demonstrated .
    OUTPUT:
    
Low lung volumes with patchy opacities in the lung bases which could reflect atelectasis but infection is not excluded .