Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: The heart is of normal size . Hilar and mediastinal contours are within normal limits . Linear opacities at the lung bases consistent with atelectasis . There is no evidence of pneumonia . Mild degenerative changes are seen in the thoracic spine . There is no pleural effusion .
    OUTPUT:
    
No acute intrathoracic process .