Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: The heart is mild to moderately enlarged . The mediastinal and hilar contours appear unchanged . There is marked lung opacification , particularly involving the right upper lobe , both lower lobes to some extent , however , and also the left perihilar region in the left upper lobe . There is no definite pleural effusion .
    OUTPUT:
    
Severe multifocal opacities , with suspicion that they most likely represent pneumonia , although a component of coinciding fluid overload is also possible .