Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: PA and lateral views of the chest were obtained with patient positioned upright . Bibasilar linear opacities could represent atelectasis , less likely reflective of pneumonia . No large effusion or pneumothorax is seen . The cardiomediastinal silhouette appears grossly stable . No acute bony abnormalities are seen .
    OUTPUT:
    
Linear densities in lower lungs , most compatible with atelectasis .