Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Bilateral low lung volumes . There is distinct increase in the interstitial markings bilaterally since chest radiograph in ___ , which is consistent with patient 's extensive interstitial lung disease as seen on previous CT in ___ and CT torso in ___ . Given patient 's extensive interstitial lung disease as also seen on CT , it is difficult to assess whether these increased markings are due to pulmonary vascular congestion or acute pneumonia . No pleural effusion or pneumothorax is seen . The cardiac size is enlarged and mediastinal silhouette is unchanged . . Pacer leads in appropriate position .
    OUTPUT:
    
Increased interstitial markings since ___ , consistent with known interstitial lung disease demonstrated on previous CT . It is difficult to assess for acute pneumonia or failure in setting of known extensive pulmonary changes .