Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: The lung volumes are low . The mediastinal and hilar contours appear unchanged . There is similar opacification of the left mid and lower lungs with air bronchograms visualized on this study . The right lung remains clear . There is no definite pleural effusion or pneumothorax , although it is difficult to exclude a pleural effusion on the left . There is no pneumothorax .
    OUTPUT:
    
Persistent left basilar opacification without definite change .