Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: The previously seen pulmonary edema has markedly improved ; however , there is still mild interstitial thickening which could represent mild pulmonary edema or interstitial lung disease . The cardiac and mediastinal contours are are unchanged . There is no pleural effusion or pneumothorax .
    OUTPUT:
    
Markedly improved pulmonary edema since ___ ; however , the current interstitial thickening could be due to mild edema or interstitial lung disease .