Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Single portable supine frontal image of the chest . Pacemaker , leads , median sternotomy wires , and mediastinal surgical clips are stable . Lung volumes are low . There has been interval increase in bilateral interstitial markings , which could be due differences in technique or to mild pulmonary edema . There is no pleural effusion or pneumothorax . The cardiomediastinal silhouette is stable from prior exam .
    OUTPUT:
    
Interval increase in bilateral interstitial markings , which could be due differences in technique or to mild pulmonary edema . If clinical concern for pulmonary edema exists , could obtain upright radiographs for better assessment of lungs .