Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: The cardiac , mediastinal , and hilar contours appear unchanged . Patchy calcification is noted along the aortic arch . The heart is at the upper limits of normal size . There is a slightly heterogeneous but predominantly diffuse bilateral interstitial abnormality which appears new since the prior examination and could be seen with interstitial pulmonary edema , mild to moderate in severity , but atypical infection could also be considered . There is , in particular , peripheral opacity layering immediately above the minor fissure and opacification of the lateral left upper lobe is also more prominent than elsewhere . More confluent infrahilar opacity on the lateral view is difficult to place on the frontal view , although likely within the left lower lobe . Fissures are slightly thickened including both major and minor fissure . However , there is no definite pleural effusion or pneumothorax . Mild rightward convex curvature is noted along the thoracic spine .
    OUTPUT:
    
New substantial interstitial abnormality , somewhat heterogeneous . Correlation with clinical presentation is recommended . This could be seen with interstitial pulmonary edema but potentially atypical pneumonia could be considered .