Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Left - sided pacemaker device is noted with leads terminating in the right atrium and right ventricle , unchanged . The heart size remains mildly enlarged but unchanged . The mediastinal and hilar contours are stable with mild calcification of the aortic knob . There is no pulmonary vascular congestion . Streaky linear opacities are seen within both lung bases , likely reflective of atelectasis . No focal consolidation , pleural effusion or pneumothorax is visualized . No acute osseous abnormalities are detected .
    OUTPUT:
    
Streaky and linear bibasilar airspace opacities most likely reflective of atelectasis .