Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Markedly widened mediastinum corresponds to a known aortic aneurysm with dissection and large mural thrombus . There are new small bilateral pleural effusions . There is no focal consolidation , pneumothorax , or pulmonary edema . The cardiac size is normal .
    OUTPUT:
    
1 . Large aortic arch aneurysm with dissection , better evaluated on chest CT from ___ . 2 . New small bilateral pleural effusions . 3 . No pneumonia .