Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: In comparison to the prior study earlier on the same day , the left hemithorax is partially opacified by layering of the previously seen small left pleural effusion . The left lower lobe remains collapsed . No pneumothorax . No significant changes compared to prior study .
    OUTPUT:
    
1 . Partial opacification of the left hemithorax by layering pleural effusion . No significant changes compared to prior study . 2 . No evidence of pneumothorax .