Wednesday, February 8, 2012

Traumatic aortic dissection-CT Angiography

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.

Isolated true anterior meningocele

Chest radiograph of 15 year old male showing mediastinal based large well defined mass lesion in the right upper hemithorax with defect in the vertebral body.

CT scan showing ventral defect in the vertebral body with herniation of meninges which is extending in to right hemithorax and displacing the trachea.

A spinal meningocele is a herniation of the meninges through a foramina or a defect in the vertebral column and is frequently located posteriorly in the lumbosacral area. 
An anterior spinal meningocele is rare and is generally described in the thoracic or sacral region. These frequently occur as a manifestation of generalized mesenchymal dysplasia such as neurofibromatosis type 1 (NF-1) or Marfan syndrome and rarely as an isolated defect.

CT and MR imaging are essential, not only for the diagnosis, but also for the depiction of its relationships to surrounding structures and the exclusion of other possible accompanying lesion such as neuroma in the setting of NF-1.

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