Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: The cardiac , mediastinal and hilar contours appear stable . There is a similar background interstitial abnormality . The previously noted opacity at the left lung base has cleared although there is mild residual more medial retrocardiac opacity , probably not new . The latter may be due to residual scarring or atelectasis . More clearly likely to represent active pneumonia , however , is a new vague opacity including nodular elements within the right upper lobe with some mild increase in background volume loss . There is no pleural effusion or pneumothorax .
    OUTPUT:
    
Findings suggest pneumonia in the right upper lobe . Follow - up radiographs are recommended to show resolution within ___ weeks . Retrocardiac opacity , probable possibly scarring or atelectasis although an additional focus of active pneumonia is not excluded by this examination .