Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Frontal and lateral chest radiographs demonstrate a normal cardiomediastinal silhouette and fairly well - aerated lungs without focal consolidation , pleural effusion , or pneumothorax . There are reticular interstitial markings with nodular opacities in the left upper lobe , which could represent viral / atypical infection . The left pulmonary artery appears enlarged . The visualized upper abdomen is unremarkable .
    OUTPUT:
    
1 . Reticular interstitial markings with left upper lobe nodular opacities , which could represent viral / atypical infection . 2 . Enlarged left pulmonary artery .