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 ___ and ___ . There is increased retrocardiac opacity , which is somewhat linear in configuration . Given low lung volumes , this could be due to atelectasis ; however , component of infection can not be excluded . Elsewhere , the lungs are clear of consolidation or effusion . Cardiomediastinal silhouette is within normal limits . Osseous and soft tissue structures are unremarkable .
    OUTPUT:
    
Probable atelectasis , noting that a component of infection can not be excluded in the proper clinical setting . Please correlate clinically .