Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Lung volumes are low . In comparison to the prior examination , there is mild central pulmonary vascular congestion , which may be exaggerated due to relative low lung volumes . No definite focal consolidation is identified . No subdiaphragmatic free air is identified .
    OUTPUT:
    
No acute intrathoracic abnormality . No evidence of subdiaphragmatic free air .