Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Lung volumes are low . Heart size is mildly enlarged but unchanged . Dense atherosclerotic calcifications are seen throughout the thoracic aorta . Mediastinal and hilar contours are unremarkable . Pulmonary vasculature is not engorged . Patchy opacities are seen in the lung bases , more so within the retrocardiac region , findings which rate may reflect atelectasis though infection is not completely excluded . No pleural effusion or pneumothorax is identified . Moderate multilevel degenerative changes are seen in the thoracic spine with compression deformity of the L1 vertebral body appearing unchanged . Previously demonstrated lytic lesion involving the left second posterior rib is better appreciated on the previous CT .
    OUTPUT:
    
Low lung volumes . Patchy opacities in the lung bases , more pronounced on the left , may reflect atelectasis but infection can not be excluded in the correct clinical setting .