A case of deceleration chest injury with severe chest pain radiating to the back, xray done in ER revealed widened superior mediastinum what is the next investigation

A case of deceleration chest injury with severe chest pain radiating to the back, xray done in ER revealed widened superior mediastinum what is the next investigation:
- conventional or ct aortography.(true)
- Plain xray survey for fracture of  the bone.