Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Lung volumes are low compared to the previous study which accentuates the size of the cardiac silhouette which is top normal . The thoracic aorta is mildly tortuous . Pulmonary vasculature is normal and the hilar contours are unremarkable . Streaky opacities in the lung bases likely reflect areas of atelectasis , without focal consolidation . No pleural effusion or pneumothorax is visualized . Partially imaged is cervical spinal fusion hardware . No acute osseous abnormality is detected . No free air is noted under the diaphragms .
    OUTPUT:
    
Mild bibasilar atelectasis .