Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: The lungs are somewhat low in volume with marked fullness of the pulmonary vasculature and increased interstitial and to a lesser degree alveolar opacities concerning for at least moderate pulmonary edema . No pleural effusion is seen . The heart is moderately enlarged with single lead pacemaker again noted .
    OUTPUT:
    
Moderate pulmonary edema , underlying infectious process not excluded .