Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Low lung volumes cause bronchovascular crowding . Left - sided perihilar interstitial opacities may be related to aspiration or infection . There is no pleural effusion , pneumothorax , or pulmonary edema . The cardiomediastinal silhouette is within normal limits .
    OUTPUT:
    
Left perihilar interstitial opacities may be due to aspiration or infection .