Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Frontal and lateral chest radiographs demonstrate unchanged exam with unremarkable cardiomediastinal and hilar contours . Stable linear opacifications noted in the bilateral lung bases , left greater than right , likely representing atelectasis . Stable blunting of the left costophrenic angle may represent small effusion versus atelectasis . Lungs are clear without evidence of septic emboli or pneumonia .
    OUTPUT:
    
Bibasilar atelectasis . Possible small left pleural effusion , unchanged from prior . No evidence of pneumonia .