Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: The previously visualized left upper lobe opacity has now resolved . The lung is free of consolidations , pleural effusions or pneumothorax . No pulmonary edema . Stable cardiomegaly . Mediastinum and hilar within normal limits . No acute osseous abnormalities .
    OUTPUT:
    
Previously visualized left upper lobe opacity has resolved . This rapid change suggests that this may have been due to asymmetrical pulmonary edema .