Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Heart size is normal with mild tortuosity of the thoracic aorta . There is mild central pulmonary vascular engorgement without frank interstitial edema . There are scattered , vague areas of increased interstitial marking slightly changed in morphology since prior exam . There is otherwise no dense consolidation . Pleural surfaces are clear without effusion .
    OUTPUT:
    
Mild central pulmonary vascular engorgement without interstitial edema but with scattered areas of new interstitial abnormality of unclear significance , could be due to acute or chronic reaction to inhaled or injected materials . No dense consolidations to suggest pneumonia .