Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Since the prior study , lung volumes have decreased , accentuating the cardiac contour and pulmonary vasculature . Diffuse interstitial abnormality may represent edema or underlying interstitial lung disease . Chronic , healed right rib fractures are again seen . No pleural effusion or pneumothorax .
    OUTPUT:
    
Low lung volumes with diffuse interstitial abnormality , reflecting edema versus underlying interstitial lung disease . No evidence of pneumonia .