Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Heart size is normal . The mediastinal and hilar contours are normal . The pulmonary vasculature is normal . Lungs are clear except for a linear focus of atelectasis or scar at the left base . No pleural effusion or pneumothorax is seen . There are no acute osseous abnormalities . The patient is status post prior median sternotomy and coronary bypass surgery .
    OUTPUT:
    
No conventional radiographic evidence of calcified pleural plaques or interstitial lung disease . CT would be more sensitive than radiographs for detecting such abnormalities in may be considered if warranted clinically .