Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: The ___ CT showed a fracture of the posteromedial left sixth rib . On the current chest x-ray , this is very subtly visible as minimal cortical offset . No significant displacement is detected on the available views . There is increased retrocardiac opacity consistent with left lower lobe collapse and / or consolidation and a small left effusion . There is subsegmental atelectasis at the right lung base . No CHF . No obvious pneumothorax . Compared with ___ at 11 :19 , I doubt overt interval change . No new infiltrate identified .
    OUTPUT:
    
Increased retrocardiac opacity , similar to ___ . Differential diagnosis includes atelectasis and / or a pneumonic infiltrate . Small left pleural effusion is similar to the prior study . Probable atelectasis at the right base , not significantly changed . As seen on the current study , the posterior medial sixth rib fracture appears only very minimally displaced , in keeping with findings on the ___ CT scan .