Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Low lung volumes exaggerate the cardiomediastinal contours . Large retrocardiac hiatal hernia is unchanged compared to multiple prior exams . There has been an interval increase in ill - defined , bilateral perihilar opacities , as well as a small right pleural effusion . Mild bibasilar atelectasis has also increased compared to the prior exam . There is no pneumothorax . The visualized osseous structures are unremarkable .
    OUTPUT:
    
1 . Interval increase in ill - defined opacities overlying the lung fields bilaterally is likely secondary to mild pulmonary edema , however an underlying infectious process can not be excluded . 2 . Stable large hiatal hernia .