Multidetector CTof Blunt Thoracic Trauma

Thoracic emegencies 2008Rathachai Kaewlai, MD • Laura L. Avery, MD • Ashwin V. As-

rani, MDRobert A. Novelline, MD

2011-06-24R2 조영관

Introduction• Thoracic injury is significant cause of

morbidity and mortality in trauma patient

• Account for 25% trauma-related death in United States

• Radiologic imaging plays an impor-tant role in the diagnosis and man-agement of blunt chest trauma

Introduction• 3rd most common injuries in trauma pa-

tients(1st:head, 2rd:extremity)• Cause 1.motor vehicle ->more than 2/3 in developed countries 2.falls or of blows from blunt object• Imaging– Conventional radiography: initial imaging– CT: significant disease

Introduction• Injuries of –1.Pleural space –2.Lungs –3.Airways –4.Heart, aorta and great vessels –5.Diaphragm–6.Chest wall

Injuries of the Pleural Space• Pneumothorax– Air collection in pleural space– Very common 15%–40% of all blunt chest

trauma– Mechanism ->ruptured alveoli due to sudden increase in

intrathoracic pressure (with or without rib fracture)

– Occult pneumothorax– Tension pneumothorax

Occult pneu-motho-rax

Tension pneu-motho-rax

Injuries of Pleural Space

• Hemothorax – Blood in pleural space– Massive hemothorax is defined as a hemothorax

exceeding 1liter with clinical signs of shock and hypoperfusion

– CT : pleural fluid with attenuation of 35–70 H.U.

• Measurement of pleural fluid attenuation should be routine in interpretation of chest trauma CT to distinguish simple fluid from acute blood

Injury of lung• Pulmonary Contusion

– Traumatic injury to alveoli with alveolar hemorrhage, but significant alveolar disruption(-) – Most common 17%–70% of all blunt chest trauma– Occurs at the time of injury, usually at the site of

impact– Resolution of pulmonary contusion typically begins

within 24-48hours, with complete clearing in 3-10days

Injuries of Lung• Pulmonary Laceration–Disruption (tear, laceration) of lung parenchyma, resulting in a cavity in lung -Because of normal pulmonary elastic recoil, lung tissue surrounding a laceration pull back

from the laceration itself. -This results in the laceration manifesting at

CT as a round or oval cavity

->Divide into 1.Traumatic pneumatocele 2.Traumatic hematocele 3.Traumatic hematopneumatocele

->Common in children & young adults - greater flexibility of chest wall

Traumatic lung herniation• Occurs when a pleura-covered part of

the lung extrudes through a trau-matic defect in the chest wall

• Usually associated with rib fracture• May increase with positive-pressure

ventilation

Injury of the airway• Tracheobrachial injuries are rare in

clinical practice because most pa-tients die before arriving at the emergency department

• Tracheobronchial injuries - 0.2%–8% of all cases of blunt chest - usually occur within 2.5 cm of ca-

rina

Injuries of Airways• Bronchial(*) & Tracheal(#) Lacera-

tion– Pneumomediastinum(*,#) pneumothorax(*) cervical subcutaneous emphysema(#)– Presence of a persistent pneumothorax Even with chest tube placement & suction - concern for possible bronchial injury

Bronchial injury

Tracheal injury

Injuries of Heart• Cause: motor vehicle collisions

- from contusion to frank rupture - most lethal injuries

• Diagnosis of blunt cardiac injury– Relies on a high degree of clinical suspicion– Imaging manifestations - hemopericardium - contrast material extravasation - pneumopericardium - displacement of heart (cardiac herniation) - abnormal bowel gas in chest (diaphragmatic pericardial tear)

Blunt cardiac injury

Injury of the aorta and great vessels

• Thoracic Aortic Injury• Usually fatal• Accounts for 10%-15% of death follow-

ing motor vehicle collisions in the United States

• 85% and 90% of patients die before reaching hospital

• Most common cause:motor vehicle col-losions

Injuries of Aorta and Great Vessels

Periaortic hematoma accompany thoracic aortic injury and is believed to represent bleeding from small veins

Periaortic hematomaConventional radiography

- false-negative CT:

- direct visualization of periaortic hematoma - show actual aortic injuries

Traumatic pseu-doaneurysmof the proximal descendingthoracic aorta

Distal descending thoracic aortic injury

Injuries of Diaphragm• 0.16%–5% in blunt trauma• Mechanism:

– Sudden increase in intraabdominal or intrathoracic Pr.– Posterolateral surface of hemidiaphragm

Injuries of the chest wall• Rib fracture -The most common skeletal injury in

blunt chest trauma -Occurs in approximately 50% of pa-

tients -Multiple or bilateral rib fracture may

indicate more severe thoracic injury

Injuries of Chest Wall

-fractures of the first through third ribs : associated with brachial plexus injury or subclavian vascular injuries-Fractures of the lower three ribs : associated with liver, spleen, & kidney in-

juries

• Flail Chest-Three or more contiguous ribs with frac-

tures in two or more places-Usually occurs anterior and anterolateral

portions of middle to lower ribs-Theses fracture create a flail segment

that can move paradoxically relative to the remainder of the chest during respi-ration

• Serves as a marker for significant in-trathoracic injury, since more than one-half of affected patients may have associated injuries requiring sirgical treatment

• These patients often require mechan-ical ventilation for prolonged period

Rib fractures and flail chest

• Sternal fracture -May result from direct blow of the

anterior chest wall -Marker for high energy trauma -Best demonstrated at CT on multi-

planar reformatted images, espe-cially sagittal images