Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Lung volumes are unchanged compared to the prior study . There has been an increase in the patchy airspace opacity seen throughout the left lung with a second more focal area in the right lower lung . Although the appearances may reflect pulmonary edema , particularly given the waxing waning appearance over the last several days , superimposed infection can not be excluded . Probable left pleural effusion . Support lines and tubes are unchanged in appearance when compared to the prior study . No pneumothorax seen .
    OUTPUT:
    
Progression of the airspace opacity in the left upper and right lower lung . As this has been waxing and waning , this may reflect pulmonary edema however infection can not be excluded .