Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: The lungs are perhaps mildly hyperexpanded , without focal opacity , pleural effusion , or pneumothorax . There is slight blunting of the left costophrenic angle , but no pleural effusion was seen shortly subsequent chest CT . The heart is normal in size with normal cardiomediastinal contours . Calcification of the aortic knob is noted . Degenerative change is seen at the right acromioclavicular joint .
    OUTPUT:
    
No acute intrathoracic process .