Imaging: Thoracic Trauma Tony Tiemesmann Diagnostic Radiology Bloemfontein Hospital Complex.

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Imaging: Thoracic Trauma Tony Tiemesmann Diagnostic Radiology Bloemfontein Hospital Complex

Transcript of Imaging: Thoracic Trauma Tony Tiemesmann Diagnostic Radiology Bloemfontein Hospital Complex.

Imaging:Thoracic Trauma

Tony Tiemesmann

Diagnostic Radiology

Bloemfontein Hospital Complex

Introduction

• Vital Structures– Heart, Great Vessels, Esophagus, Tracheobronchial

Tree, & Lungs• 25% of MVC deaths are due to thoracic trauma

– 12,000 annually in US• Abdominal injuries are common with chest trauma.• Prevention Focus

– Gun Control Legislation– Improved motor vehicle restraint systems

• Passive Restraint Systems• Airbags

Anatomy 1

• Thoracic Skeleton– 12 Pair of C-shaped ribs

• Ribs 1-7: Join at sternum with cartilage end-points• Ribs 8-10: Join sternum with combined cartilage at 7th rib• Ribs 11-12: No anterior attachment

– Sternum• Manubrium

– Joins to clavicle and 1st rib– Jugular Notch

• Body– Sternal angle (Angle of Louis)

» Junction of the manubrium with the sternal body» Attachment of 2nd rib

• Xiphoid process– Distal portion of sternum

Anatomy 2

Neuralcrest

Anatomy 3

Anatomy 4

• Mediastinum– Central space within thoracic cavity– Boundaries

• Lateral: Mediastinal pleura• Inferior: Diaphragm• Superior: Thoracic inlet• Posterior: Thoracic spine• Anterior: Sternum & costal cartilages

– Superior & Inferior mediastinum– Inferior mediastinum

• Anterior• Middle• Posterior

Anatomy 5

• Structures (superior)• Great Vessels• Oesophagus• Trachea• Nerves

– Vagus– Phrenic

• Thoracic Duct

• Structures (inferior)• Anterior – fat, lymph nodes• Middle – heart, aorta, lower SVC, Trachea & main bronchi, lymph

nodes, pulmonary veins & arteries, phrenic nerve• Posterior – Aorta, oesophagus, azygous & hemiazygous, thoracic duct,

vagus

6 weeks4 weeks

Heart

• Heart– General Structure

• Pericardium– Surrounds heart– Visceral– Parietal– Serous

» 35-50 ml fluid• Epicardium

– Outer Layer• Myocardium

– Muscular layer• Endocardium

– Innermost layer

Great Vessels

• Great Vessels– Aorta

• Fixed at three sites– Annulus

» Attaches to heart– Ligamentum Arteriosum

» Near bifurcation of pulmonary artery– Aortic hiatus

» Passes through diaphragm– Superior Vena Cava– Inferior Vena Cava– Pulmonary Arteries– Pulmonary Veins

Oesophagus

• Esophagus– Enters at thoracic inlet– Posterior to trachea– Exits at esophageal hiatus

Pathophysiology

• Blunt & Penetrating Trauma– Results from kinetic energy forces– Subdivision Mechanisms

• Blast– Pressure wave causes tissue disruption– Tear blood vessels & disrupt alveolar tissue– Disruption of tracheobronchial tree– Traumatic diaphragm rupture

• Crush (Compression)– Body is compressed between an object and a hard surface– Direct injury of chest wall and internal structures

• Deceleration– Body in motion strikes a fixed object– Blunt trauma to chest wall– Internal structures continue in motion

– Age Factors• Pediatric Thorax: More cartilage = Absorbs forces• Geriatric Thorax: Calcification & osteoporosis = More fractures

Cardiovascular 1

• Myocardial Contusion– Occurs in 76% of patients with severe blunt chest trauma– Right Atrium and Ventricle is commonly injured– Injury may reduce strength of cardiac contractions

• Reduced cardiac output

– Electrical Disturbances due to irritability of damaged myocardial cells

Cardiovascular 2

• Pericardial Tamponade– Restriction to cardiac filling caused by blood or other

fluid within the pericardium– Occurs in <2% of all serious chest trauma

• However, very high mortality

– Results from tear in the coronary artery or penetration of myocardium• Blood seeps into pericardium and is unable to escape• 200-300 ml of blood can restrict effectiveness of cardiac

contractions– Removing as little as 20 ml can provide relief

Cardiovascular 3

• Myocardial Aneurysm or Rupture– Occurs almost exclusively with extreme blunt thoracic

trauma– Secondary due to necrosis resulting from MI– Signs & Symptoms

• Severe rib or sternal fracture• Possible signs and symptoms of cardiac tamponade• If affects valves only

– Signs & symptoms of right or left heart failure• Absence of vital signs

Cardiovascular 4

• Traumatic Aneurysm or Aortic Rupture– Aorta most commonly injured in severe blunt or penetrating

trauma• 85-95% mortality

– Typically patients will survive the initial injury insult• 30% mortality in 6 hrs• 50% mortality in 24 hrs• 70% mortality in 1 week

– Injury may be confined to areas of aorta attachment– Signs & Symptoms

• Rapid and deterioration of vitals• Pulse deficit between right and left upper or lower extremities

Cardiovascular 5

• Other Vascular Injuries– Rupture or laceration

• Superior Vena Cava• Inferior Vena Cava• General Thoracic Vasculature

– Blood Localizing in Mediastinum– Compression of:

• Great vessels• Myocardium• Esophagus

Oesophagus

• Traumatic Esophageal Rupture– Rare complication of blunt thoracic trauma– 30% mortality– Contents in esophagus/stomach may move into

mediastinum• Serious Infection occurs• Chemical irritation• Damage to mediastinal structures• Air enters mediastinum

– Subcutaneous emphysema and penetrating trauma present

Imaging: Radiography

• NB NB• Delay only in life-threatening conditions• Haemo/Pneumothorax• Fractures (ribs - flail chest)• Mediastinum – widened, air• Diaphragmatic rupture• Foreign bodies

Imaging: Computed tomography

• Blunt lung trauma – blood in bronchi, interstitial blood• Cardiac & major vessel trauma (with or without angio)

– critical area to evaluate on CT scans is the aorta at the level of the left main pulmonary artery (90% of all CT-detected aortic injuries begin at or just above this level and that 85% of aortic injuries end at or just below it)

• CTA• Bony elements & surrounding tissue

Imaging: MRI

• Stable patients• CT unequivocal• NB: vascular and spinal injuries

Imaging: Ultrasound

• Quick & non-invasive• FAST (focussed assessment for sonographic evaluation of

the trauma patient)• Percardiac – percardiocentesis • Sternum• Pleural• Pulmonary contusion• Diaphragm• NB: Degree of confidence

Imaging: Echocardiography

• Acute blunt cardiac injury – chamber disruption, valvular incompetence, coronary artery thrombosis, ventricular aneurysm formation, myocardial contusion

• Detectable functional changes – cardiac function, motion abnormalities of the cardiac wall, pericardial effusions, valvular injury

Imaging: Angiography

• Widened mediastinum on CXR (3% aortic injury)• Aortogram – rupture/pseudoaneurysm

Imaging: Nuclear medicine

• Continuing symptoms with no radiological signs• Skeletal - technetium-99m diphosphonate • Cardiac - thallium-201 chloride

Trauma Imaging 1

Trauma Imaging 2

Trauma Imaging 3

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Trauma Imaging 5

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Trauma Imaging 10

References

• Kaewlai R, Avery L, Asrani A, Novelline R. Multidetector CT of Blunt Thoracic Trauma. RadioGraphics 2008; 28:1555–1570.

• Jin W, Yang DM, Kim HC, Ryu KN. Diagnostic values of sonography for assessment of sternal fractures compared with conventional radiography and bone scans. J Ultrasound Med. Oct 2006;25(10):1263-8; quiz 1269-70.

• Gavelli G, Canini R, Bertaccini P. Traumatic injuries: imaging of thoracic injuries. Eur Radiol. Jun 2002;12(6):1273-94.

• Khan AL et al. Trauma thoracic imaging. Medscape Oct 2011.• DiMaio VJM, Dana SE. Handbook of forensic pathology 2nd ed. CRC

Press. 2006.