Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Lung volumes are persistently low . This accentuates the size of the cardiac silhouette which appears at least moderately enlarged but unchanged . Widening of the mediastinal contour is likely reflective of the low inspiratory lung volumes and is similar to the prior study . Mediastinal and hilar contours are otherwise unremarkable . There is crowding of the bronchovascular structures without overt pulmonary edema . Patchy opacities in the lung bases likely reflect areas of atelectasis though infection is not completely excluded . No large pleural effusion or pneumothorax is identified . Marked degenerative changes are again noted throughout the imaged thoracolumbar spine without a definite acute abnormality .
    OUTPUT:
    
Low lung volumes with patchy opacities at the lung bases , likely atelectasis . Infection however is not completely excluded .