Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Linear opacity is identified at the left lung base . The lungs are otherwise clear focal consolidation or large effusion for overt pulmonary edema . The cardiomediastinal silhouette is within normal limits for technique .
    OUTPUT:
    
Linear left basilar opacity . While this may be due to atelectasis , infection would also be possible in the proper clinical setting .