Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Similar to multiple prior examinations , the exam is limited due to patient positioning . Given that , lung volumes are persistently low . Bilateral opacities are again demonstrated and may be increased from the prior examination raising the possibility of infection or aspiration . Cardiomediastinal contours can not be evaluated due to patient positioning . .
    OUTPUT:
    
Low lung volumes . Bilateral pulmonary opacities appear increased from the prior examination could represent atelectasis , aspiration or infection .