Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: The cardiac , mediastinal and hilar contours appear stable . Patchy opacity at the left base suggests minor atelectasis . There is no pleural effusion or pneumothorax . Fissures are mildly thickened . However , there is no convincing evidence for parenchymal edema . Bony structures are unremarkable .
    OUTPUT:
    
No evidence of pneumonia .