Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: The heart size is normal . The aorta demonstrates mural calcifications . The mediastinal and hilar contours are otherwise unremarkable , and there is no evidence of pulmonary vascular engorgement . Ill - defined patchy opacity in the left lung base may reflect an area of atelectasis . No focal consolidation , pleural effusion or pneumothorax is identified . No acute osseous abnormality is visualized .
    OUTPUT:
    
Left basilar patchy opacity likely reflective of atelectasis , though infection can not be completely excluded .