Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Frontal and lateral views of the chest are compared to previous exam from ___ . There is patchy left basilar opacity , more conspicuous on the frontal than on the lateral . Elsewhere , the lungs are clear . There is no effusion . Findings suggest small hiatal hernia . Cardiomediastinal silhouette is otherwise unchanged . Osseous and soft tissue structures are unchanged , noting hypertrophic changes in the spine .
    OUTPUT:
    
Left basilar opacity , potentially atelectasis ; however , infiltrate from infection is not excluded . Clinical correlation suggested .