Chest trauma

Imaging in thoracic trauma and complications

1. IMAGING IN CHEST
TRAUMA
Dr.Rashmi Burlakoti
FCPS Resident,Bir hospital

2. •Injuries to the thorax are the third most common injuries in
trauma patients, next to injuries to the head and
extremities
•Mechanism
Blunt Trauma
Penetrating Trauma
Compression Injury.

3. Blunt Injury
•Either:
direct blow (e.g. rib fracture)
deceleration injury
compression injury
•Rib fracture is the most common sign of blunt thoracic
trauma
•Fracture of scapula, sternum, or first rib suggests
massive force of injury

4. Penetrating injuries
E.g. stab wounds etc.
Primarily peripheral lung
Hemothorax
Pneumothorax
Cardiac, great vessel or oesophageal injury

5. •Acutely injured pts
–CXR AP supine
–CT ( MDCT preferable)
•If patients condition allows
CXR
PA erect preferable
Lateral film-helpful
High KV-desirable to see mediastinal
structure
CT, Aortography and TEUS
in suspicious vascular injury.
Ultrasound
Pleural collection, diaphragm and
subphrenic area

6. Rib fracture
•The most common skeletal injury in blunt chest trauma
•occurs in approximately 50% of patients.
•Fractures of the 1st three ribs
–imply severe trauma
–may be associated with vascular, brachial plexus, spinal, or
tracheobronchial injury.
•Fractures of the last three ribs (10th to 12
th
)
–a/w injuries to the liver, spleen, or kidneys.

7. •Stress fracture of 1
st
and 2
nd
rib-sometimes an incidental
finding
•Cough fracture-6
th
to 9
th
rib, posterior axillary line. May not be
visible until callus formation.

8. •Chest radiography is routinely used to assist in the diagnosis
of rib fractures, even though it has limited sensitivity.
•CT is the most sensitive technique for imaging rib fractures
-helps to determine the site and number of fractures
-provide information regarding any associated injuries.

9. Complication of rib fracture
1.Flail segment
2.Pneumothorax
3.Hemothorax
4.Neurovascular injury ( first 3 ribs)
5.Abdominal visceral injury ( last 3 ribs)
6.Subcutaneous emphysema

10. Flail Chest
•three or more contiguous ribs with
fractures in two or more places.
•usually occur in the anterior and
anterolateral portions of the
middle to lower ribs.
•These fractures create a flail
segment that can move
paradoxically relative to the
remainder of the chest during
respiration in a spontaneously
ventilating patient.

11. Flail Chest

12. Flail chest.CT image of a left-sided flail chest with a segment of the chest wall pushed
inwards.

13. Fracture of sternum
•Mortality -high (25%) owing to associated injuries (cardiac
contusion, pulmonary contusion and haemothorax).
•Results from deceleration injury or direct blow to anterior chest
•commonly involve the sternalbody and the manubrium
•Diagnosis by lateral radiograph
•best demonstrated at CT on multiplanarreformatted images,
especially sagittal images
•On occasion, a fracture line may be difficult to detect at axial CT,
and the clue to the diagnosis may be the presence of anterior
mediastinalhemorrhage

15. •Clavicle fracture
–be a/w injury to subclavian vessels or brachial plexus
•Sternoclavicular joint dislocations
-may be either anterior or posterior
–Posterior dislocation of the clavicle can cause injury to the
trachea, oesophagus, great vessels or nerves of superior
mediastinum.
•CXR can detect fracture or dislocation. CT is more accurate to
assess fracture and superior mediastinal structures. MRI to
assess nerves in particular

16. FRACTURE OF SCAPULA
•Uncommon, occuring in 3.7% of patient with multiple
injuries
•Mechanism:
-direct blow to the scapula or an indirect axial force
transmitted through the humerus.
-Motor vechicle collison or fall from height.
•associated with other injuries—including pneumothorax,
hemothorax, pulmonary injuries, and spinal injuries
•Most fractures involve the body and neck of the scapula

17. Fracture of thoracic spine
•occur in around 9% of multiple trauma cases
•~1/3
rd
cases -cord injuries with neurological deficit.
•Common site of fracture-T9–T11
•Mechanism of fracture-
–hyperflexion and/or axial loading,
–In MVA or fall from a height.
•Thoracic spine fractures often missed initially as the clinical and
radiographic signs can be overshadowed by other injuries.

18. •Radiological investigation
–CXR with high kV
•An initial evaluation.
•Findings-fracture, paraspinal hematoma
•In suspicious fracture further evaluation is needed.
–MDCT
•Increasingly used in cases of non-trivial thoracic trauma.
•Number of studies have shown improved sensitivity of MDCT
compared with plain radiographs.
–MRI
•To assess the spinal cord.

19. Injury to the pleura
1.Pneumothorax
2.Hemothorax
3.Hemopneumothorax
4.Empyema-in open injury leading to infection.

20. Traumatic Pneumothorax
•Causes
–Complication of rib fracture
–Secondary to pneumomediastinum, pulmonary laceration
or penetrating chest injuiry.
–Sudden rise of intraalveolar pressure during blunt trauma.

21. •10%–50% of pneumothoraces from blunt trauma are not
visualized at chest radiography performed in supine patients
but can be seen at CT
•pneumothoraces seen only at CT are called “occult
pneumothoraces”

22. •CXR
–Diagnosed by visualizing the visceral pleura as a sharp thin
line with absent lung markings beyond.
–Difficulty may occur with supine radiographs where air
collects anterior to the lung and there is no visible lung
edge.

23. •The diagnosis of an occult pneumothoraxon a “supine”
radiograph relies on several signs,Including
(a)increased lucencyat the affected lung base –lucent cardio-
phrenicsulcus
(b) the “deep sulcus” sign,an abnormally deep costophrenic
sulcus
(c) the “double diaphragm” sign
(d) better definition of mediastinalcontour.

24. Left-sided pneumothoraxseen on a supine chest radiograph demonstrating
the deep sulcus sign and an unusually sharp left heart border

25. CT image demonstrating a very
small right anterior post-traumatic
pneumothorax
•CT
–much more sensitive than
the chest radiograph to
detect pneumothorax.
–can detect the smallest of
pneumothoraces.
–Detection is important as
even a small
pneumothorax can
increase in size rapidly if
the patient receives
positive-pressure
mechanical ventilation.

26. Tension Pneumothorax
•When air collects in the pleural space to the point where the
intrapleural pressure exceeds that of the atmosphere, a
tension pneumothorax occurs
•it may be suggested at imaging when the following signs are
present in addition to the pneumothorax:
(a) mediastinal shift to the contralateral side,
(b) flattening or inversion of the ipsilateral hemidiaphragm,and
(c) hyperexpanded ipsilateral chest –ipsilateral lung collapse.

27. Tension pneumothorax following a transbronchial lung biopsy. Eversion of the right
hemidiaphragm, and deviation of the mediastinum to the opposite side. The diffuse
bilateral infiltrate is due to pre-existing pulmonary haemorrhage.

28. Tension Pneumothorax.CT chest of a post-traumatic pneumothorax. Despite the presence of an
intercostal drain, a tension pneumothorax was developing as the drain was blocked with
congealed blood. The right-sided pneumothorax is situated anteriorly and the mediastinum is
displaced to the left due to the tension.

29. Hemothorax
•Causes
–Complication of rib fracture
–Secondary to pulmonary laceration or penetrating chest
injury
•Source of bleeding
–Laceration of intercostal or pleural vessels or pulmonary
vessels.
•Small hemothorax if blood originates from the low-pressure
pulmonary circulation as a result of lung contusion or laceration,
•Large and life-threatening hemothorax if bleeding arises from
large pulmonary vessels or from systemic vessels, such as the
internal mammary arteries.

30. •May be a/w pneumothorax ( hemopneumothorax)
•Massive hemothorax is defined as a hemothorax exceeding 1
liter with clinical signs of shock and hypoperfusion
•CT readily characterizes pleural fluid in the setting of trauma
with determination of the attenuation value. Blood in the
pleural space typically has an attenuation of 35–70 HU.

31. Injury to the lung
•Pulmonary contusion
•Pulmonary laceration
•Torsion of the lung
•Atelectasis and compensatory hyperinflation
•Pulmonary edema ( manifestation of ARDS in trauma)
•Fat embolism -rare complication of multiple fractures.

32. Pulmonary contusion
•Pulmonary contusion occurs in up to 75% of cases of blunt
chest trauma.
•Traumatic injury to the alveoli with alveolar hemorrhage, but
without significant alveolar disruption
•Imaging of contusion
–CXR
–CT chest

33. The typical imaging appearance consists of:
•patchy airspace opacities or consolidations with ill-defined
borders that are distributed irrespective of
bronchopulmonary segmental anatomy (nonsegmental
distribution).
•At CT, subpleural sparing (1–2 mm of clear parenchyma
beneath the pleural surface) may be observed

34. •CT can often help detect pulmonary contusion immediately
after injury
•visualization at conventional radiography may not
be possible until up to 6 hours later
•Resolution of pulmonary contusion typically begins within
24–48 hours, with complete clearing in 3–10 days

35. •Focal areas of pulmonary opacity appearing 24 hours or more
after injury suggest diagnoses other than contusion, including
aspiration
•patients who have pulmonary contusion are at increased risk
for developing pneumonia and respiratory distress syndrome.

36. Pulmonary contusion and haematoma following blunt trauma. (A) Extensive consolidation is presentthroughout both
lungs,particularly in the left upper zone. Bilateral pleural tubes and a nasogastric tube (arrows) are present. (B) Six days later the
contusion has resolved and multiple pulmonary haematomas and some extrapleural haematomas have become visible. (C) One
month later the haematomas are smaller

37. Pulmonary contusion. (A) CT image in the axial plane and (B) coronal
reformatted image illustrating bilateral post-traumatic pulmonary contusion.
Note the subpleural predominance of the contusion.

38. Pulmonary laceration
•Severe blunt trauma may induce shearing forces that lead to
parenchymal disruption.
•Owing to the elastic recoil of the lung, the resultant tear
quickly becomes a space that can fill with blood, creating a
haematoma, or with air, resulting in a pneumatocele, or both.
•Haematomas and pneumatoceles are usually small (2–5 cm)
but can be larger.
•Typically resolve over a period of months.

39. •Four types of lung laceration have been described according to
mechanism of injury, CT pattern, and location of associated rib
fractures:
Type 1 laceration (compression rupture injury) :
Most common type of pulmonary laceration, where direct
compressive force results in lacerations in a deep portion of
the lung.
Type 2 laceration (compression shear injury) :
caused by a severe, sudden blow to the lower hemithorax,
resulting in a sudden shift of the lower lobes of the lungs
across the spine.
These lacerations are seen in the paraspinal region

40. Type 3 laceration (rib penetration tear) :
located in the periphery of the lungs where a rib has been
fractured and is generally associated with pneumothorax.
Type 4 laceration (adhesion tear)
in the region of preexisting pleuropulmonary adhesion and is
usually diagnosed at surgery or autopsy.
Pulmonary laceration is common in children and young adults
because they have greater flexibility of the chest wall,
resulting in a higher likelihood of lung injury with blunt
trauma.

41. •Imaging ( CXR and CT chest)
–Hematoma: homogenous round opacity
–Pnematocele: thin walled loculated air collection within the
lung
–Both component: Air fluid level if pneumatocele is partly
filled with blood.
–may be single or multiple and unilocular or multilocular in
appearance
–In early stage, findings may be obscured by surrounding
contusion. As contusion( consolidation) resolves laceration
becomes evident.

43. Traumatic Lung Herniation
•Traumatic lung herniation occurs when a pleura covered
part of the lung extrudes through a traumatic defect in the
chest wall . This condition is usually associated with rib
fractures.

44. Torsion of a lung
•rare result of severe thoracic trauma,
•usually in child.
•The lung twists about the hilum through 180°.
•If unrelieved the lung may become gangrenous and appear
opaque on the chest X-ray.
Atelectasis and compensatory hyperinflation after a chest injury
•may be due to aspiration of blood or mucus into the bronchi.
•may also occur secondary to decreased respiratory
movement

45. Fat embolism
•Rare complication of multiple fractures, due to fat
globules from the bone marrow entering the systemic veins
and embolising to the lungs.
-Poorly defined nodular opacities appear throughout both
lungs; the opacities resolve within a few days.
•diagnosis is confirmed if fat globules are present in the
sputum or urine.

46. Injury to trachea and bronchi
•Fracture of 1
st
three ribs often associated.
•Common site of injury of tracheobronchialtree
–In 90% -mainstembronchus , 10% -trachea, within 2 cm of
the carina
•Mechanism : sudden chest compression against a closed
glottis or compression of the airways between the sternum
and thoracic spine
•If bronchial sheath is preserved, no immediate Sign or
symptoms. However, tracheostenosisor bronchiectasis
develop later.

47. •Imaging findings( CXR, CT chest)
–Fracureof rib ( 1
st
three)
–Progressive/persistent mediastinalemphysema and
pneumothorax which typically fails to respond to a chest
drain.
–With complete rupture of a mainstembronchus, the lung
may sag to the floor of the pleural cavity—the ‘fallen lung
sign’—as the intact vessels are unable to support the lung
•The lung falls inferiorly if the patient is upright and posteriorly
if the patient is supine
–CT maydirectly show the tracheobronchialinjury.

48. •Bronchial lacerations are more common than tracheal
lacerations and are typically parallel to the cartilage rings of the
bronchi.
•Tracheal lacerations are usually vertical and longitudinal and
located at the junction of the cartilaginous and membranous
portions of the trachea
•Common findings of tracheal lacerations are cervical
subcutaneous emphysema and pneumomediastinum.

49. Fallen lung sign.Chest radiograph in a patient injured in a farming accident. The right
lung is seen sagging to the floor of the right hemithorax (the ‘fallen lung sign’) and a
completely ruptured right main bronchus was found at surgery.

51. Injury to mediastinum
•Pneumomediastinum
•Mediastinal hemorrhage
•Aortic rupture
•Cardiac injury
–Pneumopericardium
–Hemopericardium
–Myocardial contusion
•Oesophageal rupture

52. Pneumomediastinum
•Presence of air bet tissue planes of mediastinum
•Causes
–Macklin effect: Alveoli rupture along base, air then tracks
through pulmonary interstitium and then decompresses
into the mediastinum
–10% incidence with blunt chest trauma
–Perforation of trachea/bronchi or oesophagus
–Penetrating lung injury

53. Signs pneumomediastinum
–Interstitial air
•air around pulmonary artery and main branches :ring around artery
sign
•air outlining major aortic branches :tubular artery sign
•Double bronchial wall (air on both sides of airway)
–Subcutaneous emphysema (neck and chest wall)
–Continuousdiaphragm sign
–V sign of Naclerio
•Costovertebral air adjacent to left hemidiaphragm and spine,
raises question of esophageal tear
–Thymic sail sign /spinnaker sign/angel wing sign(pediatric
patients)
–Air in the pulmonary ligament

56. Double Bronchial Sign
•Air in the mediastinum
and left main bronchus
allows visualization of
both sides of the
bronchial wall.

57. Spinnaker Sign (Thymic Sail Sign)
With sufficient
mediastinal air, the
thymus can become
elevated, creating the
Thymic Sail Sign, or
Spinnaker Sign.

58. V sign of Nacleiro

59. Pneumomediastinum vs pneumopericardium
Pneumomediastinum Pneumopericardium
Gas often outlines the aortic knuckle
and extends into the neck
Gas doesnot extend beyond the
aortic root or much beyond the pulm
artery
Distribution of air does not changes
with pts position.
changes
Continuous diaphragm sign seen
-Continuous diaphragm sign seen
More common in neonates and
infants and may displace the
thymus.
-

60. Mediastinal hemorrhage
•May result from penetrating or non-penetrating trauma
•Due to venous or arterial bleeding
•Imp causes
–MVA
–Aortic rupture and dissection
–Introduction of central venous catheters.
•Many cases may be unrecognised as clinical and radiological
signs are absent. Usually b/l mediastinal wideningoccur.
There may be localised hematomaas well.

61. Mediastinal haematoma. Following unsuccessfully attempted
placement of a central venous line via the right subclavian vein, a large
extrapleural haematoma (arrows) is present.

62. Traumatic rupture of aorta
•Traumatic aortic rupture is the cause of 16% of MVA deaths.
•Location:
Aortic isthmus:90%
proximal descending aorta ,
aortic arch,
aortic root, and
Distal descending aorta at the aortic hiatus

63. •In the majority of survivors the tear involves the intima and
media with the adventitia remaining intact and maintaining
aortic integrity for a time.( PSEUDOANEURYSM)
•With complete rupture the adventitia is also disrupted and is
normally associated with mediastinal haemorrhage which (if
the patient survives) may progress to apical pleural capping
and haemothorax

64. CXR supine
The radiograph must be studied for signs of mediastinal haematoma and therefore
possible aortic rupture . These signs include:
•Widening of the mediastinum--width above the level of the carina of 8 cm or more
or, Mediastinum >25% of the width of the chest at this level.
•NB-donot give too much weight on absolute values if the subjective impression is of
a wide mediastinum.
•Blurred contour of the aortic arch and filling in of AP window.
•A left apical pleural cap due to extrapleural haematoma and possibly a left pleural
effusion.
•Deviation of the trachea or a nasogastric tube to the right
•Displacement of the left main stem bronchus ant., inf. & to rt.
•Widening of the right paratracheal stripe and the paraspinal lines.

65. MDCT
•CT signs of aortic injury
–direct signs
–Indirect signs
•direct signs
–pseudoaneurysms and intimal flaps,
•indirect sign
–peri-aortic haematoma

66. Angiography
•Angiographic signs of traumatic aortic rupture
–irregularity of the aortic isthmus,
–pseudoaneurysm formation and
–presence of a linear radiolucency across the aorta.
•angiography is now seldom performed as a diagnostic
study but may be performed as an adjunct to
endovascular stent insertion.

67. Aortic rupture and mediastinal haematoma.Chest radiograph in a patient with a post-traumatic
aortic rupture and mediastinal haematoma. Features present include a widened mediastinum,
filling in of the aortopulmonary bay and the development of a left apical pleural cap.

68. Aortic dissection.(A) Axial and (B) sagittal reformatted CT images following a high
speed road accident. An acute post-traumatic aortic dissection can be seen along with
a small amount of mediastinal haematoma.

69. Injury to diaphragm
•The diaphragm can be ruptured by both blunt and penetrating
trauma.
•Mechanism of rupture in blunt trauma
–A frontal impact to the abdomen ----massive, sudden rise in
intra-abdominal pressure----rupture. In this situation, tears
are usually 10 cm or more in length, are radially orientated
and occur at the weakest part of the diaphragm, namely the
musculotendinous junction in a posterolateral location.
–Lateral impacts in MVA ----compression of the thorax
towards the vertebral body-----stretch and tear the
diaphragm.

70. •Complications may be
–Bowel herniationor strangulation.
–Rupture of herniated bowel into pleural space and
empyema.
–Abdominal contents adjacent to the lung lead to impaired
ventilation and atelectasis.

71. Associated injuries
•Associated injury present if sufficient kinetic energy applied to
rupture the diaphragm
•With right-sided tears
–Hepatic, bowel laceration.
–Thoracic injury
•With left-sided tears
–Splenic injuries
–Thoracic injury

72. CXR findings
•Nonvisualization of diaphragmatic contour
•Abnormally elevated hemidiaphragm contour
•Contralateral shift of mediastinum
•Lower thoracic soft tissue density mass/ abnormal gas density
Herniated hollow/fluid-filled viscus (stomach, colon, small bowel)
Herniated solid organ (spleen, liver, kidney)
Herniated omental fat
Loculated hydropneumothorax
•Site of diaphragmatic tear: Focal constricted gas-filled bowel loop("collar" sign)
•Visualization of nasogastric (NG) tube above left hemidiaphragm
•May have unusual course with tip directed back toward left shoulder
•Pleural effusion, contusion, atelectasis, & phrenic nerve palsy can mask diaphragmatic injury
Fluoroscopic Findings
•"Collar" sign: Focally constricted (site of tear) contrast-filled bowel loop partly in thorax and
abdomen
On upper GI series or barium enema

73. CT Findings
•Discontinuity of hemidiaphragm
•Intrathoracic herniation of abdominal contents
•"Collar" sign
Left side: Waist-like constriction of stomach or colon at site of diaphragmatic tear
Right side: Same constriction of herniated portion of liver
•Abdominal contents lateral to diaphragm
•"Fallen"or "dependent" viscus sign
Herniated viscus abuts posterior ribs, thoracic wall. Normally, should be
suspended by diaphragm, away from body wall
•"Dangling diaphragm" sign
Free edge of torn diaphragm curls inward, rather than continuing its normal
course parallel to chest wall
•Active extravasation of contrast near diaphragm
•Penetrating diaphragmatic injury: Depiction of trajectory of missile or puncturing
instrument
•Localized soft tissue swelling

74. •MR Findings
•Normal diaphragm on T1 and T2WI
–Continuous hypointense band
•Traumatic diaphragmatic hernia
–Abrupt disruption of diaphragmatic contour
–Intrathoracic herniation of abdominal fat or viscera
–Coronal and sagittal planes can both be useful
•Diaphragm is generally easier to visualize on MR than on CT
–MR generally more appropriate for evaluation of stable
patient, not in acute trauma setting

75. Figure 8.Left diaphragmatic tear in a 24-year-old woman who was injured in a motor vehicle
accident.
Iochum S et al. Radiographics 2002;22:S103-S116
©2002 by Radiological Society of North America

76. Diaphragmatic rupture. Chest radiograph showing a left-sided diaphragmatic rupture. Bowel can be
seen herniating into the left hemithorax, the mediastinum is displaced to the right and there is a
nasogastric tube seen coiled within an intrathoracic stomach.

78. CT signs of blunt diaphragmatic injury
CT signs DIRECTSIGNS INDIRECTSIGNS
Segmental diaphragmaticdefect Collar sign
Dangling diaphragm Herniated viscera
Absent diaphragm Dependent viscera
haaga page no. 1134

79. Oesophageal rupture
•usually the result of instrumentation or surgery , penetrating
trauma,
•rarely spontaneous
•due to sudden increase of intraoesophageal pressure
(Boerhaave's syndrome).
•radiographically there are signs of pneumomediastinum,
with or without a pneumothorax or hydropneumothorax,
which is usually left-sided.
•The diagnosis should be confirmed by a swallow. This should
initially be with water-soluble contrast medium in order to
avoid the small risk of granuloma formation in the
mediastinum that has been described following barium
leakage.

80. THANK YOU

81. REFERENCES:
1) Text Book of radiology and imaging by David Sutton 7th edition
2) Multidetector CT of blunt thoracic trauma by Rathachai Kaewlai, et al ,RSNA 2008