Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Again seen is opacification of the posterior segments of the left lower lobe and the basilar segments of the left lower lobe compatible with known post-obstructive pneumonia . The right lung is clear . There may be a small left pleural effusion . There is no pneumothorax . A right Port - A - Cath catheter terminates in the SVC . The cardiomediastinal silhouette is unchanged . The bones are intact .
    OUTPUT:
    
Post-obstructive left lower lobe pneumonia , unchanged from previous exams .