Traumatic aortic injury

Clinical History

Patient was transferred from another hospital to cardiosurgery department of our hospital because of suspected traumatic dissection of ascending thoracic aorta.

Imaging Findings

Patient was transferred from another hospital to cardiosurgery department of our hospital because of suspected traumatic dissection of the ascending thoracic aorta. Two days before admission in our hospital she was involved in high-speed head-on car colission and sustained multiple injuries including: serial rib fractures of both sides, fractures of both claviculae, left sided temporoparietofrontal lamellar subdural haematoma, right femoral fracture, and two smaller parenchymal spleen laceration. Multi-detector row helical computed tomography (MDCT) of the chest reavealed both sided pleural effusions, mediastinal haematoma, and dissection of ascending thoracic aorta was suspected. Next day after admission control MDCT of the chest showed progression of pleural effusions and patient was transferred to cardiosurgery department of our hospital. MDCT performed in our hospital revealed both sided pleural effusions, mediastinal haematoma, and a 2,3x1,5 cm saccular outpouching of the aortic isthmus and traumatic pseudoaneurysm was diagnosed. Two smaller parenchymal spleen lacerations was also confirmed. At surgery about 4 cm long incomplete rupture of the aortic isthmus was found protected with haematoma. Interposition graft was placed at the site of the injury. Four days later ostheosinthesis of the right femoral fracture was performed. The other lesions were succssefuly treated conservatively. Sixty fife days after admission patient was discharged from our hospital to the rehabilitation centre.

Discussion

Traumatic injuries of the thoracic aorta is a rare but most dangerous condition of chest trauma. If unrecognised and untreated has 90% mortality at 4 month.(1,2) Severe deceleration in high speed motor vehicle collisions is the most common cause of thoracic aorta injury.(1,3,4) The most common site of thoracic aorta rupture is aortic isthmus, segment between the origin of the left subclavian artery and the attachment of the ligamentum arteriosum, found in 90-95% of the surviving patients. The injuries of the ascending aorta and aortic root are usually fatal, found in only 5% of the survivors, but in 22% of the cases at autopsy. Less than 3% of injuries occur in the descending aorta at the level of the diaphragm.(1,5) The initial method of examination for trauma patients is chest radiography usually obtained using a portable radiography unit. Well documented findings of mediastinal haematoma on the chest radiograph as are: widening of the superior mediastinum with lose of the aortic knob contour, left apical pleural cap, deviation of the nasogastric tube or trachea to the right, depression of the left mainstem bronchus greater than 40 degrees, loss of the descending aorta line may suggest traumatic aortic injury (TAI).(1,5) Catheter angiography was traditionally used to diagnose TAI with the sensitivity close to 100% and specificity of approximately 98%.(5) But catheter angiography is an invasive procedure with possible complication. MDCT has an increasing role in the diagnostic evaluation of TAI. Image acquisitions in multiple phases allows diagnostic work-up not only of vascular system but also injuries of parenchymal organs. Improved z-axis spatial resolution results in high quality multiplanar and 3D images reconstruction; maximum intensity projection (MIP), and volume rendering techniques (VRT) obviating the need for angiography before surgery, and allowing to plan endovascular interventional treatment.(4) Computed tomography findings of aortic injury include: intimal flap, intraluminal areas of low attenuation, calibre change in the aorta, pseudoaneurysm, irregularity of the aortic wall or contour, contrast material extravasation. (4,5) Reported sensitivity, specificity, and accuracy of MDCT angiography in the detection of blunt traumatic aortic lesions is 96%, 99%, and 99% respectively.(4) Normal mediastinum at CT with no haematoma and a regular aorta surrounded by normal fat has a 100% negative predictive value for aortic injury.(4) Treatments of acute traumatic rupture and chronic posttraumatic aneurysm of thoracic aorta are open surgery or endovascular stent grafting with similar results.(3)

Differential Diagnosis List

Final Diagnosis

incomplete traumatic rupture of the aortic isthmus

URL:	https://eurorad.org/case/4985
DOI:	10.1594/EURORAD/CASE.4985
ISSN:	1563-4086