Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Heart size is mildly enlarged but unchanged . The mediastinal and hilar contours are unremarkable . Pulmonary vasculature is not engorged . Linear opacities in the left lung base likely reflect areas of atelectasis . No focal consolidation , pleural effusion or pneumothorax is present . There are moderate multilevel degenerative changes noted in the lower thoracic spine . Deformity of the left proximal humerus is compatible with a remote fracture .
    OUTPUT:
    
Left basilar atelectasis .