Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: The visualized mediastinal structures are within normal limits . There is no cardiomegaly . There are mild degenerative changes seen in the thoracic spine , no significant change as compared to prior examination . The visualized lung fields are clear without evidence of focal consolidation . There are no pneumothoraces or effusions seen .
    OUTPUT:
    
Clear lung fields without evidence of acute cardiopulmonary process .