Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Cardiomediastinal shadow unchanged . Hilar shadows unchanged . Background of increased interstitial markings with a mid to lower lung zone predominance . No consolidation . Round calcification in the right mid lung zone unchanged . No effusions . Mild spondylotic changes of the thoracic spine .
    OUTPUT:
    
Increased interstitial markings with a mid to lower lung zone predominance . In the differential consider interstitial edema ( but there is no cardiomegaly , vascular congestion or pleural effusion ) or viral / atypical infection .