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Imaging in Thoracic Trauma
1. IMAGING IN
THORACIC TRAUMA
WAN NAJWA ZAINI WAN MOHAMED
RADIOLOGIST, HOSPITAL QUEEN ELIZABETH II
1st Sabah Thoracic Surgical Update, 5 â 6 Oct 2018
2. CONTENTS
⢠INTRODUCTION
⢠ANATOMY OVERVIEW
⢠IMAGING TOOLS
⢠RADIOLOGICAL SIGNS/ FEATURES
1st Sabah Thoracic Surgical Update, 5 â 6 Oct 2018
4. INTRODUCTION
⢠Trauma is a leading cause of death in developing countries | 4th in first-world
countries
⢠Loss of productive years of life â because most occur in young individuals
⢠Traffic accidents, falls, recreational, violence
⢠Rapid diagnosis important to avoid morbidity and mortality
1st Sabah Thoracic Surgical Update, 5 â 6 Oct 2018
5. INTRODUCTION
⢠Thoracic injuries
ď10-15% of all trauma, 25% of trauma fatalities
⢠Mechanism of trauma
ďDirect Injury â Blunt, Penetrating, Baro Trauma, Radiation Trauma
ďIndirect Injury â Complication Of Remote Injury/ Treatment
⢠Blunt Chest Injury
ďCauses â MVA (75%), fall, blow, blast, violent action
ď30% require hospital admission
1st Sabah Thoracic Surgical Update, 5 â 6 Oct 2018
6. INTRODUCTION
⢠Penetrating Injury
ďCauses: Fracture of rib, gunshot, stab
ďPermanent cavity inside the tissue, crushed, expansion
ďProjectile passes through â tract
⢠Blunt (70-80%) > penetrating
â Compression ď thoracic wall injuries
â High velocity injury ď visceral injuries
⢠Rx mostly conservative. Thoracotomy rate <10% in blunt, 15-30% in penetrating
thoracic trauma
1st Sabah Thoracic Surgical Update, 5 â 6 Oct 2018
14. IMAGING TOOLS
1. Chest Radiograph
ďPortable
2. Ultrasound (as a part of extended FAST)
ďBedside
3. CT Scan
ďmost accurate
1st Sabah Thoracic Surgical Update, 5 â 6 Oct 2018
Initial survey /
âscreening toolâ
15. Chest Radiograph
⢠Views
ďPreferably AP erect
ďCXR in expiration â detect small pneumothorax
ďAP supine at the end of inspiration
ďDecubitus - suspected side up
⢠Supine radiograph is most difficult to analyse, under reporting is common
1st Sabah Thoracic Surgical Update, 5 â 6 Oct 2018
16. Chest Radiograph
⢠Indications
ďTube and line malposition â most critical
ďThoracic cage injury, Flail chest
ďPneumothorax, Hemothorax
ďPneumomediastinum, pneumopericardium
ďLung contusion/ laceration
ďMediastinal widening
ďDiaphragm injury
ďOthers âspine fractures
1st Sabah Thoracic Surgical Update, 5 â 6 Oct 2018
17. 2. Ultrasound (eFAST Scan)
⢠Extended FAST (eFAST) very useful for quick pericardial and pleural spaces
evaluation in chest trauma
⢠Can detect 15 - 20 ml of fluid
⢠Studies have shown excellent sensitivities and specificities approaching 100%
⢠Able to decrease time to operative intervention, patient length of stay, cost,
rates of complications, CTs, and DPLs performed
⢠Limitations : operatorâs experience, patientâs body habitus, presence of
subcutaneous emphysema, pneumoperitoneum or pneumomediastinum
1st Sabah Thoracic Surgical Update, 5 â 6 Oct 2018
18. 2. Ultrasound (eFAST Scan)
PERICARDIAL EVALUATION
⢠Curvilinear probe
⢠Technique
ďB-mode (grey scale)
ďSubcostal/ subxiphisternum â
transverse plane, liver as window
⢠Indications
ďHaemopericardium
ďCardiac Tamponade
PLEURAL EVALUATION
⢠Curvilinear/ linear probe Technique
ďB mode, M mode if B mode
equivocal
ďAnterior thoracic - longitudinal
plane along midclavicular line at 3rd
â 4th intercostal space
⢠Indications
ďPneumothorax
ďHaemothorax
1st Sabah Thoracic Surgical Update, 5 â 6 Oct 2018
19. 3. CT Scan
⢠Most accurate for diagnosis of several thoracic trauma
⢠Yield of CT is higher when done after an abnormal initial CXR or performed
selectively based on clinical criteria
⢠Patient preparation
ďHemodynamic â must be stable
ďIV contrast â a must
ďRenal function test â risk/benefit ratio
ďPregnancy test â yes if status unknown/ in doubt
⢠CT Technique
ďHelical mode
1st Sabah Thoracic Surgical Update, 5 â 6 Oct 2018
20. 3. CT Scan
ďNo plain scan
ďThinnest collimation possible and 2 â 2.5mm multiplanar reformation
ďLate arterial phase + delays for vascular injuries
⢠Indications
ďInjuries of pleural space
ďInjuries of lungs, airways
ďInjuries of heart, oesophagus
ďInjuries of aorta and great vessels
ďInjuries of diaphragm
ďInjuries of chest wall
1st Sabah Thoracic Surgical Update, 5 â 6 Oct 2018
22. RADIOLOGICAL SIGNS &
ASSESSMENT
⢠Isolated sign not common. Usually in combination
⢠E.g. Fractured ribs might cause major injury to the lung parenchyma
(contusion, laceration and hemorrhage) and other complications
⢠Recap:
1st Sabah Thoracic Surgical Update, 5 â 6 Oct 2018
Table 1: Attenuation of the X-Ray beam
Tissue absorption Effect on the radiograph
Least Air or gas
Fat
Soft tissue
Most Bone or
calcium
Black image
Dark grey image
Grey image
White image
24. 1. Tubes/ Lines
Tubes/ Lines Malposition
⢠Ideal position of ETT tip = 5 ¹ 2 cm
above carina @ T2 to T4 level
⢠Tip position changes depending on
neck position and rotation
ďmay change by up to 2 cm
ďneck flexion ďŽ tip downwards
ďneck extension ďŽ tip upwards
⢠In children, optimum position is 1.5
cm above carina
1st Sabah Thoracic Surgical Update, 5 â 6 Oct 2018
Right mainstem bronchial intubation
25. 1. Tubes/ Lines
1st Sabah Thoracic Surgical Update, 5 â 6 Oct 2018
Left chest tube â chest wall placement NG tube â looped around carina
Case courtesy of A.Prof Frank Gaillard, Radiopaedia.org, rID: 32358
26. 2. Soft Tissue
Subcutaneous emphysema
⢠Most common cause: trauma
⢠Presence of air locules in the
subcutaneous tissue or muscle
plane. May track to the neck and
abdominal wall.
⢠Hyperlucencies in the subcutaneous
tissue or along muscle plane
âGingko leaf signâ
1st Sabah Thoracic Surgical Update, 5 â 6 Oct 2018
27. 3. Thoracic Cage
Rib fracture
⢠Most frequent 4-10
⢠If 8-12, should suspect associated
abdominal injuries
⢠1st to 3rd rib fractures considered
high energy trauma, often
associated with major intrathoracic
or cranial injuries
1st Sabah Thoracic Surgical Update, 5 â 6 Oct 2018
28. 3. Thoracic Cage
Flail Chest
⢠Most significant chest wall injuries
⢠Associated with high impact
⢠When 3 or more contiguous
segmental ribs fractured in 2 or
more places
⢠Affected wall sunken in during
inspiration
⢠Patients often require mechanical
ventilation for prolonged periods
1st Sabah Thoracic Surgical Update, 5 â 6 Oct 2018
29. 3. Thoracic Cage
Clavicle fracture
⢠most common chest wall injuries
⢠80% occur in middle third
Scapular fracture
⢠Uncommon
Sternal fracture
⢠Usually associated with high energy
trauma
⢠Commonly at body, manubrium
Sternoclavicular dislocation
⢠Anterior â more common, benign
course
⢠Posterior â more serious, assoc. with
major intrathoracic injuries
1st Sabah Thoracic Surgical Update, 5 â 6 Oct 2018
30. 4. Pleura
Pneumothorax
⢠Air in the pleural space
⢠Causes:
ďFractured rib penetrates the lung
parenchyma
ďRapid acceleration-deceleration
ďBarotrauma â IPPV
ďCardiopulmonary resuscitation
⢠Signs in upright CXR:
ďVisible visceral pleural edge as a thin
sharp white line
ďNo lung markings peripheral to line
⢠Signs in supine CXR:
ďHyperexpanded hemithorax
ďIncreased lucency
ďIncreased sharpness of heart border
ďDeep sulcus sign â when air collects
laterally and deepens the lateral
costophrenic angle
ďDouble diaphragm sign â when air
outlines anterior portions of
hemidiaphragm, anterior costophrenic
sulcus visualized
1st Sabah Thoracic Surgical Update, 5 â 6 Oct 2018
34. 4. Pleura
Tension Pneumothorax
⢠Air leak from lung parenchymal injury, increasing pressure within
⢠Mediastinal displaced away
ďdecreased venous return
ďcompressing opposite lung
⢠Hemodynamically unstable, can progress to complete cardiovascular collapse
⢠Immediate decompression needed
1st Sabah Thoracic Surgical Update, 5 â 6 Oct 2018
35. 1st Sabah Thoracic Surgical Update, 5 â 6 Oct 2018
Postmortem CXR. Image from trauma.org
36. 4. Pleura
Haemothorax
⢠Blood in pleural space
⢠Source: chest wall, lung parenchyma, heart or great vessels
⢠In 25-50% of patients with blunt chest trauma and 60-80% of patients with
penetrating wounds
⢠Radiographic features similar to pleural effusion
⢠Massive hemothorax when >1,500 mL of blood or > 1/3 of blood volume
⢠Tension haemothorax â massive intrathoracic bleeding causing ipsilateral
lung compression and mediastinal displacement
1st Sabah Thoracic Surgical Update, 5 â 6 Oct 2018
38. 4. Pleura
⢠eFAST very high sensitivity (92%), and specificity (100%)
⢠CT useful to evaluate nature of pleural fluid in the setting of trauma by
assessing the attenuation value. Blood attenuation 35-70 HU
1st Sabah Thoracic Surgical Update, 5 â 6 Oct 2018
Case courtesy of Dr Andrew Dixon,
Radiopaedia.org, rID: 31555
39. 4. Pleura
Haemopneumothorax
⢠When there is concurrent presence
of a haemothorax and
a pneumothorax
⢠Concurrently occur in 5% of patients
with pneumothorax
1st Sabah Thoracic Surgical Update, 5 â 6 Oct 2018
40. 5. Lung
Contusion
⢠Interstitial and/or alveolar lung injury
without any frank laceration
⢠Usually occurs secondary to non-
penetrating trauma
⢠CXR:
ďNot sensitive
ďFaint patchy consolidative regions
following history of blunt trauma
ďUsually shows rapid improvement with
time in days
1st Sabah Thoracic Surgical Update, 5 â 6 Oct 2018
41. 5. Lung
⢠CT :
ďTypically seen as focal non
segmental (typically crescentic)
areas of parenchymal opacification
ďCan have sub-pleural sparing
with smaller contusions which
can be a distinguishing feature
ďCommoner posteriorly and in
lower lobe
1st Sabah Thoracic Surgical Update, 5 â 6 Oct 2018
42. 1st Sabah Thoracic Surgical Update, 5 â 6 Oct 2018
5. Lung
Laceration
⢠Results from frank laceration of lung parenchyma secondary to trauma, there is
almost always concurrent contusion
⢠Classification :
ďType I : compression rupture
ďType II : compression shear
ďType III : direct puncture / rib penetration
ďType IV : adhesion tears
⢠CXR:
ďLinear tear that becomes round or ovoid (pneumatocele) with time
ďCan be similar to contusion. Gaseous lucencies may be seen in or adjacent to the
areas of consolidation
43. 1st Sabah Thoracic Surgical Update, 5 â 6 Oct 2018
5. Lung
ď May be difficult to appreciate, often obscured by surrounding lung contusion,
consolidation and hemothorax.
44. 5. Lung
⢠CT:
ďRegions of pulmonary contusion
and blebs (pneumatocoeles) with
air fluid levels
ďDue to normal pulmonary elastic
recoil, lung tissues surrounding a
laceration often pull back from the
laceration itself, manifesting as a
round or oval cavity
ďPneumatocoeles appear as 'holes'
in the lung parenchyma âSwiss
cheese signâ
1st Sabah Thoracic Surgical Update, 5 â 6 Oct 2018
Case courtesy of Dr Domenico Nicoletti, Radiopaedia.org, rID: 38519
45. 5. Lung
Fat Embolism
⢠Lipid emboli from bone marrow enter
pulmonary and systemic circulation
⢠Usually occurs in the context of a long
bone fracture
⢠1 to 2 days post-trauma, resolves in 1-4
weeks
⢠CXR:
ďCan resemble ARDS
ďWidespread homogeneous &
heterogeneous opacities
1st Sabah Thoracic Surgical Update, 5 â 6 Oct 2018
46. 5. Lung
⢠CT:
ďAreas of consolidation
ďGround-glass opacities with
geographic distribution and/or
interlobular septal thickening
ďSmall (<1cm) nodular opacities
ďFatty filling defects in pulmonary
arteries â rare
1st Sabah Thoracic Surgical Update, 5 â 6 Oct 2018
47. 1st Sabah Thoracic Surgical Update, 5 â 6 Oct 2018
6. Trachea & Bronchi
Tracheobronchial Injury
⢠1.5% of major thoracic trauma, 30%
missed
⢠80% within 2.5 cm of carina (blunt
trauma)
⢠Can be identified in 70% of CT
⢠Bronchoscopy gold standard
⢠CXR:
ďSubcutaneous emphysema
ďPneumothorax
ďPneumomediastinum
ďBronchial injury â pulmonary alveolar
rupture âMacklin effectâ
Case courtesy of Dr Bruno Di Muzio, Radiopaedia.org, rID: 59456
48. 1st Sabah Thoracic Surgical Update, 5 â 6 Oct 2018
7. Mediastinum
Aortic Injury
⢠Critical life threatening condition
⢠16% MVA fatalities, more with blunt
trauma
⢠85-90% mortality prior to reaching
hospital
⢠90% of aortic ruptures occur just
distal to the origin of the left
subclavian artery
49. 7. Mediastinum
⢠CXR (related to signs of mediastinal
haematoma):
ďWidening of the mediastinum > 8 cm
at aortic arch level
ďTracheal or NG tube deviation to the
right
ďWidening of right paraspinal or
paratracheal stripe
ďLoss of aortopulmonary window
ďindistinct aorta definition
ďLeft apical cap sign
ďNormal in 10-15%
1st Sabah Thoracic Surgical Update, 5 â 6 Oct 2018
Case courtesy of Dr Andrew Dixon, Radiopaedia.org, rID: 45368
50. 1st Sabah Thoracic Surgical Update, 5 â 6 Oct 2018
7. Mediastinum
⢠CT may show indirect signs:
ďMediastinal hematoma
ďPeriaortic fat stranding
ďOther chest injuries
⢠CTA :
ďźSigns of mediastinal hematoma
ďAbnormal soft tissue density
around the mediastinal structures
ďLocation is important, periaortic
hematoma much more suggestive
than isolated mediastinal
hematoma remote from aorta
ďźSigns of aortic injury :
ďIntraluminal filling defect (intimal
flap or clot)
ďAbnormal aortic contour (mural
hematoma)
ďPseudoaneurysm
ďExtravasation of contrast
51. 1st Sabah Thoracic Surgical Update, 5 â 6 Oct 2018
Case courtesy of Dr Sophie O'Dowd, Radiopaedia.org, rID: 47799
53. 7. Mediastinum
Pneumomediastinum
⢠Presence of extraluminal gas within the mediastinum.
⢠Gas may originate from lungs, trachea, bronchi, oesophagus, peritoneal
cavity and track from mediastinum to neck or abdomen
⢠CXR:
ďźSmall amounts of gas appear as linear or curvilinear lucencies outlining
mediastinal contours:
ďAnterior to the pericardium - pneumopericardium
ďAround the pulmonary artery or its major branches âring around artery signâ
1st Sabah Thoracic Surgical Update, 5 â 6 Oct 2018
54. 7. Mediastinum
ďAround the aorta or its major branches âtubular artery signâ
ďAround the bronchial tree âdouble bronchial wall signâ
ďTrapped posterior to pericardium âcontinuous diaphragm sign
ďSubcutaneous emphysema
ďPediatric â elevated thymus âspinnaker sail signâ
1st Sabah Thoracic Surgical Update, 5 â 6 Oct 2018
55. 1st Sabah Thoracic Surgical Update, 5 â 6 Oct 2018
Case courtesy of Radswiki, Radiopaedia.org, rID: 11791
56. 7. Mediastinum
Pneumopericardium
⢠Gas does not extend beyond aortic root
or main pulmonary artery
⢠Occasionally difficult to differentiate
with pneumomediastinum
Pneumo Gas extension Air distribution
Mediastinum Outline aortic
knuckle
Little or no change on
positioning
Pericardium Aortic root,
MPA
Alter with positioning
1st Sabah Thoracic Surgical Update, 5 â 6 Oct 2018
57. 7. Mediastinum
Haemopericardium
⢠Accumulation of blood in the pericardium
⢠Source: Great vessels, heart, pericardial vessels
⢠CXR:
ď>250 mL is necessary to be detectable
ďSubpericardial fat stripe measures >10 mm
ďSymmetrical enlargement of cardiac silhouette (water-bottle sign)
⢠eFAST:
ďFluid (anechoeic) around the heart
ďCardiac Tamponade â collapsed right heart chambers (RV specific), distended
IVC
1st Sabah Thoracic Surgical Update, 5 â 6 Oct 2018
59. 7. Mediastinum
Oesophageal Rupture
⢠A rare but serious medical emergency
with a very high mortality rate
⢠CXR:
ďNon-specific
ďUsually show wide mediastinum,
pneumomediastinum, left pleural
effusion, hydropneumothorax
⢠Contrast Enhanced Esophography :
ďExtravasation of contrast material into
the mediastinum
1st Sabah Thoracic Surgical Update, 5 â 6 Oct 2018
60. 7. Mediastinum
⢠CT :
⢠Focal esophageal wall thickening
⢠Periesophageal fluid collections
⢠Free mediastinal air
⢠Contrast extravasation into the
mediastinum and pleural space
1st Sabah Thoracic Surgical Update, 5 â 6 Oct 2018
61. 1st Sabah Thoracic Surgical Update, 5 â 6 Oct 2018
8. Diaphragm
Diaphragmatic rupture
⢠In 3-7% of patients with blunt and 6-46% of patients with penetrating
thoraco-abdominal trauma
⢠90% of tears occur on the left side
⢠CXR:
ďLoss of the normal hemidiaphragm contour
ďHerniated stomach or bowel above the diaphragm with or without focal
constriction of the viscus at the site of the tear âcollar signâ
ďLeft hemidiaphragm much higher than the right
63. 1st Sabah Thoracic Surgical Update, 5 â 6 Oct 2018
8. Diaphragm
⢠CT:
ďźDirect CT Signs
ďSegmental Diaphragmatic Defect â focal and abrupt loss of continuity in the
diaphragm
ďDangling Diaphragm â the free edge of the torn diaphragm which curls inward
from its normal course toward the center of the body forming a comma shaped
or curvilinear structure
ďAbsent Diaphragm â absence of part or all of the hemidiaphragm without
demonstration of a tear
64. 1st Sabah Thoracic Surgical Update, 5 â 6 Oct 2018
8. Diaphragm
ďźIndirect CT Signs :
ďHerniation through a Defect
ďCollar Sign
ďHump and Band Signs
ďDependent Viscera Sign
ďSinus Cut-off Sign
ďAbdominal Content Peripheral to
the Diaphragm or Lung Sign
ďElevated Abdominal Organs Sign
65. 1st Sabah Thoracic Surgical Update, 5 â 6 Oct 2018
9. Others
Spine fracture
⢠Multiple in 10%
⢠Thoracic spine injuries have a much higher incidence of neurological deficit than
cervical or lumbar spine injuries
Cord trauma
⢠25% spine fractures
⢠90% neurologic injury
⢠Most common site = T9-11
Nerve root trauma
⢠Especially to the brachial plexus