Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Compared with prior radiographs of ___ , there is an opacity at the right lung base which obscures the right hemidiaphragm and right heart border , with elevation of the right hemidiaphragm , suggestive of right middle and lower lobe volume loss , with possible right pleural effusion . The left lung is clear . There is no pulmonary edema or pneumothorax . Cardiomediastinal silhouette is unchanged .
    OUTPUT:
    
Right basilar opacity with elevation of the right hemidiaphragm , likely represents right middle and lower lobe volume loss , and possible right pleural effusion .