Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: There is persistent left basilar opacity . , unchanged compared to the prior study . Again this may reflect a combination of pleural effusion and atelectasis versus pneumonia . The right basilar opacities are unchanged . No additional areas of concern are identified in the bilateral lungs . The cardiomediastinal contour is within normal limits . No pneumothorax seen . The free air seen under the right hemidiaphragm , consistent with the patient 's recent surgery .
    OUTPUT:
    
No significant interval change when compared to the prior study . Persistent airspace opacity in the left lower lobe may reflect a combination of pleural effusion and atelectasis however pneumonia can not be excluded .