Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: The patient is status post coronary bypass surgery . The cardiac , mediastinal and hilar contours appear stable . A patchy but extensive opacity in the left upper lobe suggesting pneumonia has improved to some extent . The right lung remains clear . There is perhaps a trace pleural effusion on the left , but no definite right - sided effusion . There is a moderate hiatal hernia . The cardiac , mediastinal and hilar contours appear stable .
    OUTPUT:
    
Improvement in left upper lobe consolidation . Follow - up radiographs within eight weeks are recommended to show resolution .