Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Moderate cardiomegaly is stable compared to exams dating back to at least ___ . The hilar and mediastinal contours are normal . Small bilateral pleural effusions are persistent . Opacity at the left lung base , with obscuration of left hemidiaphragm appears similar to the prior exam and is likely secondary to atelectasis , however retrocardiac consolidation on the lateral radiograph appears to have progressed compared to the prior exam from ___ , and is concerning for pneumonia . There is no evidence pneumothorax . The visualized osseous structures are unremarkable .
    OUTPUT:
    
Left lower lobe opacity concerning for pneumonia .