CT of Thorax represents:

Aoic dissection (AD) occurs when an injury to the innermost layer of the aoa allows blood to flow between the layers of the aoic wall, forcing the layers apa. The diagnosis of aoic dissection is based on clinical suspicion combined with imaging studies. Chest x-ray will sometimes show a "widened mediastinum". This occurs because the enlarged aoa casts a larger shadow on the x-ray detector. If this is seen, and there is a high clinical suspicion of a dissection, a CT scan of the chest with intravenous contrast is ordered REF: DAVID SUTTON 7TH ED