Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Heart size is normal . The mediastinal and hilar contours are normal . The pulmonary vasculature is normal . Lung volumes are low . Minimal patchy retrocardiac opacity likely reflects atelectasis , with no evidence for focal consolidation . No pleural effusion or pneumothorax is seen . There are no acute osseous abnormalities .
    OUTPUT:
    
Minimal patchy retrocardiac opacity likely reflects atelectasis in the setting of low lung volumes .