Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Lordotic positioning . Compared with ___ and allowing for technical differences , I doubt significant interval change . Slightly streaky appearance the retrocardiac region is similar to the prior film and may reflect subsegmental atelectasis . No focal infiltrate or frank consolidation is identified . No effusion . Cardiomediastinal silhouette is unchanged and not enlarged . No CHF . No pneumothorax detected .
    OUTPUT:
    
Possible left lower lobe atelectasis . No focal pneumonic infiltrate or consolidation .