Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Comparison is made to a prior examination of ___ . The heart size is at the upper limits of normal . The lung volumes are low due to poor inspiratory effort . Opacities in the retrocardiac region . The pulmonary vasculature is normal . There are no large pleural effusions .
    OUTPUT:
    
1 . Low lung volumes due to poor inspiratory effort . 2 . Retrocardiac opacities may represent atelectasis , pneumonia can not be excluded .