28 year old male patient came to emergency with road traffic accident, emergency thoracic CT angiography showed dissection of aortic arch distal to the left subclavian artery. Note the intimal flap (arrow) with true and false lumen (Type B dissection).
Up to 15% of all deaths following motor vehicle collisions are due to injury to the thoracic aorta. Many of these patients are dead at scene from complete aortic transection. Patients who survive to the emergency department usually have dissection, small tears or partial-thickness tears of the aortic wall with pseudoaneurysm formation.
Chest radiograph has a low sensitivity and has got high negetive predictive value (98%). Most sensitive indicator is abnormal appearing mediastinum, mediastinal widening of more than 8 cm at the level of aortic arch. Sensitivity of CT scan with the advent of MDCT is increased and is 97 to 100%. Intimal flap with true and false lumen are seen clearly.
Treatment is edovascular stent graft in type B dissection and surgical management if it is type A.