Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: There has been improved aeration of the lung bases with slight residual remaining in the retrocardiac left lower lobe . Mild prominence of the pulmonary vasculature is evident and which may be in part indicative of underlying interstitial edema . There has been prior median sternotomy . The cardiac silhouette remains borderline enlarged but stable . No definite effusion or pneumothorax is seen . The osseous structures are unremarkable .
    OUTPUT:
    
Mild interstitial edema , likely cardiogenic in etiology . Recommend repeat radiography after appropriate diuresis to assess for underlying infection .