Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Lung volumes are low . This accentuates the size of the cardiac silhouette which is mildly enlarged . Mediastinal and hilar contours are unchanged . There is crowding of bronchovascular structures without overt pulmonary edema . Increased opacity within the retrocardiac region likely reflects atelectasis . No pleural effusion or pneumothorax is present . There are moderate multilevel degenerative changes in the thoracic spine .
    OUTPUT:
    
Low lung volumes with retrocardiac opacity , likely reflective of atelectasis . Infection or aspiration can not be excluded in the correct clinical setting .