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 increased parenchymal opacity in the retrocardiac region confirmed on the lateral view . Elsewhere , lungs are clear . Cardiomediastinal silhouette is normal . Osseous and soft tissue structures are unremarkable .
    OUTPUT:
    
Left base opacity compatible with pneumonia . Given history of recent treatment for pneumonia this could potentially be resolving . However , there is no prior exam available for direct comparison of this finding . Repeat exam in several weeks is recommended to document complete resolution .