Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Patient is status post median sternotomy and ascending thoracic aorta dissection repair with similar appearance of the superior mediastinal contour . Lung volumes are low . Moderate enlargement of the cardiac silhouette is re - demonstrated . There is crowding of bronchovascular structures with probable mild pulmonary vascular congestion . A small left pleural effusion is noted . There is atelectasis at the lung bases without focal consolidation . Assessment of the left apex is obscured by the patient 's neck and chin projecting over this area . No acute osseous abnormalities seen .
    OUTPUT:
    
Low lung volumes with probable mild pulmonary vascular congestion and trace left pleural effusion . Bibasilar atelectasis .