Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Lung volumes are may be slightly low , though is probably background hyperinflation , with flattened diaphragms . Rotated positioning . The heart is not enlarged , though there is left ventricular configuration . Aorta is calcified and tortuous . There is minimal atelectasis / scarring at both lung bases . No CHF , focal infiltrate or gross effusion is identified . No pneumothorax is detected . Slight blunting of the costophrenic angles posteriorly is noted .
    OUTPUT:
    
Probable background COPD . Bibasilar atelectasis . Slight blunting of the costophrenic angles posteriorly . Allowing for this , no acute pulmonary process identified . No focal infiltrate to suggest pneumonia .