Radiological findings of Thoracic and abdominal trauma modified

CT Scan findings of thoracic and abdominal trauma

1. CT SCAN IN EVALATUATION OF THORACIC AND ABDOMINA TRAUMA MODERATORS : DR . L. NATH (PROFESSOR & HOD) DR . P. BORAH DR . D. J. BORPATROGOHAIN DR . P N TAYE DR. S. S. BISWAS PRESENTER : DR. VENKATESH

2. Trauma : leading cause of death under 40 years of age pulmonary trauma : common in high-impact injuries. Most common types of lung parenchymal injury : contusions, lacerations hematomas . Chest radiography : first-line imaging modality. CT images :accurate for the assessment of the nature and extent of pulmonary injury.

3. More than two-thirds of blunt thoracic trauma is caused by motor vehicle collisions (MVCs), while the remainder result from falls from height or direct impact to the chest. Penetrating injuries : gunshot / stab / blast injuries and penetration from other objects.

4. Sternal fracture Heart injury Rib fracture Pulmonary contusion, laceration Upper rib fracture (first three ribs) Brachial plexus, subclavian vessels     Lower rib fractures (last four ribs) Intra-abdominal injury Subcutaneous emphysema Airway injury, oesophageal injury Pneumomediastinum Airway injury, lung injury, oesophageal injury Sternoclavicular fracture (posterior sternoclavicular dislocation) Mediastinal vessels, tracheal injury, oesophageal injury Scapular fracture Haemopneumothorax , lung injury, spine and clavicle fracture, subclavian vessels, brachial plexus Table

5. The chest radiograph is the primary initial screening examination performed in thoracic trauma, although some centres also perform extended focused assessment in sonography for trauma ( eFAST ). Chest radiography : 1] Identify rib fractures 2 ] Foreign bodies / ballistic fragments 3 ] C ontusions , 4 ] Pneumothorax 5 ] Hemothorax & mediastinal injuries Contrast-enhanced CT : standard imaging tool in the evaluation of trauma patients . (Greater sensitivity and specificity)

6. M ost commonly associated with rib fractures that lacerate the lung. Tracheobronchial always associated with pneumothorax. CT is more sensitive. Radiographic signs : Increased lucency at the affected hemidiaphragm, An abnormally deep costophrenic sulcus sign, A sharply defined radiolucent border of the mediastinum or heart, and The “ double diaphragm sign ” caused by the presence of air outlining the dome and insertion of the diaphragm.

7. Pneumothorax following blunt chest trauma. (a) Supine AP chest radiograph shows displaced left rib fractures, subcutaneous emphysema, and subtle pneumothorax. There is a significant basilar pneumothorax with several imaging clues: deep sulcus sign, double diaphragm sign, and a well-defined left heart border with floating fat pad sign. Multiple opacities are depicted throughout the left lung, compatible with a combination of contusions and lacerations in the setting of trauma. (b) Axial CT image obtained on the same day as a shows a large pneumothorax; a radiograph can significantly underestimate pneumothorax size. Two intraparenchymal lacerations are depicted in the left lower lobe, with pneumatocele and hematopneumatocele .

8. A tension pneumothorax is due to a one-way valve mechanism that allows air into but not out of the pleural space, thereby allowing the pleural pressure to exceed atmospheric pressure. Findings: collapse of the ipsilateral lung, contralateral mediastinal deviation, and inversion of the ipsilateral diaphragm. Since tension pneumothorax is a clinical diagnosis, and patients may have mediastinal deviation without clinical signs of tension physiology (impaired venous return to the heart), likely due to loss of negative intrapleural pressure on the affected side.

9. Erect AP/PA view is best Shift of mediastinum /heart/trachea away from pneumothorax side Depressed hemidiaphragm Degree of lung collapse is variable

10. Posteroanterior chest radiograph in a 29-year-old man with shortness of breath shows findings of tension pneumothorax, including collapse of the ipsilateral lung, contralateral mediastinal deviation, and inversion of the ipsilateral diaphragm.

11. Tension haemopneumothorax. Axial contrast-enhanced CT at mediastinal window shows a right tension haemopneumothorax with heterogeneous increased density due to presence of blood clots and a significant shift of the mediastinum contralaterally.

12. Tension pneumothorax. Sagittal reformatted CT image at lung window showing tension pneumothorax with significantly collapsed lung at the posterior part of the hemithorax associated with ipsilateral pleural effusion.

13. Haemothorax: In 50% of chest trauma cases . B lood pooling into the pleural space from variable sources: the lung parenchyma, the chest wall, the great vessels, the heart or even the liver and spleen through diaphragmatic rupture. Arterial bleeding more common. CT: very sensitive in detecting even a small haemothorax.

14. Tracheobronchial injuries are rare, occurring in 0.2 – 8% of all cases of chest trauma. Bronchial injuries: more commonly than tracheal, usually on the right side and within 2.5 cm from the carina. 85% of tracheal lacerations occur 2 cm above the carina. A direct CT finding of tracheobronchial injuries is the cutoff of the tracheal and bronchial wall with extraluminal air surrounding the airway. Indirect findings are the “ fallen lung ” sign, corresponding to the collapsed lung resting away from the hilum towards the dependent portion of the hemithorax.

15. Bronchial transection . A 22-year-old man involved in a car accident. Volume-rendered image of the tracheobronchial tree showing complete transection of the right intermediate bronchus.

16. Tracheal injury in a 32-year-old man after a thoracic gunshot wound. (a) AP radiograph shows entry and exit sites . The AP bullet trajectory would be expected to involve midline structures such as the trachea. Paramediastinal haziness is depicted, reflecting pulmonary contusions. (b) Axial contrast-enhanced chest CT image shows extensive diffuse pneumomediastinum. Note the small anterior tracheal wall defect. Tracheal injury from a penetrating wound would likely be associated with injury to other adjacent mediastinal structures as well. (c) Parasagittal contrast-enhanced reformatted CT image shows extensive anterior and posterior pneumomediastinum from the visualized neck to the root of the aorta.

17. Contusion: Blood in intact lung parenchyma Laceration: Blood in torn lung parenchyma Chest film cannot differentiate them. Contusions peak in 2-3 days, begin to resolve in a week; lacerations take much longer to resolve and may leave scars.

18. AAST Organ Injury Scale for Lung Injury Grade Injury Type Description of Injury I Contusion Unilateral contusion, segmental or subsegmental involvement II Contusion Unilateral contusion, lobar involvement   Laceration Peripheral laceration, with or without simple pneumothorax III Contusion Unilateral contusion with more than single lobe involvement or bilateral contusions   Laceration Persistent laceration (>72 hours); injury to distal airways, with or without air leak   Hematoma Intraparenchymal hematoma (nonexpanding) IV Laceration Major laceration (segmental or lobar) with imaging findings suggestive of air leak   Hematoma Expanding intraparenchymal hematoma (expanding over consecutive imaging examinations or with active contrast material extravasation)   Vascular injury Primary branch intrapulmonary vessel disruption V Vascular injury Hilar vascular injury (contained, without active contrast material extravasation) VI Vascular injury Transection of pulmonary hilum or hilar vessel injury with uncontained bleeding (active contrast material extravasation)

19. Lung contusion is a focal parenchymal injury caused by disruption of the capillaries of the alveolar walls and septa, and leakage of blood into the alveolar spaces and interstitium . It is the most common type of lung injury in blunt chest trauma. M ain mechanism: compression and tearing of the lung parenchyma at the site of impact against osseous structures, rib fractures or pre-existing pleural adhesions. Lung contusion occurs at the time of injury, but it may be undetectable on chest radiography for the first 6 h after trauma. The pooling of haemorrhage and oedema will occur at 24 h, rendering the contusion radiographically more evident, although CT may readily reveal it from the initial imaging.

20. The appearance of consolidation on chest radiography after the first 24 h should raise suspicion of other pathological conditions such as aspiration, pneumonia and fat embolism. Contusions appear as geographic, non-segmental areas of ground-glass or nodular opacities or consolidation on CT that do not respect the lobar boundaries and may manifest air bronchograms if the bronchioles are not filled with blood. Subpleural sparing of 1 – 2 mm may be seen, especially in children. Clearance of an uncomplicated contusion begins at 24 to 48 h with complete resolution after 3 to 14 days. Lack of resolution within the expected time frame should raise the suspicion of complications such as pneumonia, abscess or ARDS.

21. Lung contusion. Axial (a, b) and coronal (c) CT images at lung window show nodular opacities of ground-glass opacity that do not respect the lung boundaries of the right upper lobe. (A), diffuse areas of ground-glass opacity in the upper lobes bilaterally with subpleural sparing (b) and multiple areas of consolidation with air bronchograms and small lacerations in both lungs consistent with lung contusions.

22. Pulmonary laceration occurs in major chest trauma when disruption and tearing of the lung parenchyma follows shearing forces, caused by direct impact, compression or inertial deceleration. C lassified into the following four types according to the mechanism of injury: type I   -  compression rupture: most common type of laceration that usually occurs as a 2-8 cm lesion in the central lung. type II  - compression shear: occurs after sudden compression of the lower chest when the lung suffers from a shear injury to the spine; the lung is compressed by lateral compression, against the spine leading to a paravertebral tubular lesion   in lower part of the lung. type III -  direct puncture / rib penetration: occur with a penetrating fractured rib; these lesions are commonly multiple. type IV -  adhesion tears: occurs in sudden injuries of the chest wall where prior  pleuropulmonary adhesions  have been created.

23. Pulmonary laceration in a 38-year-old man after a thoracic gunshot wound. (A) AP chest radiograph obtained at presentation shows a hazy opacity in the left upper lobe, reflecting laceration obscured by pulmonary contusions. (B) axial CT image obtained on the same day better shows the pulmonary laceration cavity filled with blood and air, with surrounding contusion. (C) AP radiograph obtained 8 days later shows that the laceration is visible as a well-circumscribed opacity, as the contusions have resolved. Note the persistent pneumothorax, possibly from a bronchopleural fistula, a potential complication of large pulmonary lacerations.

24. Pulmonary laceration types 1–3. (A) axial CT image in a 27-year-old man shows three centrally located intraparenchymal lacerations type 1, compression rupture ( pneumatocele and hematopneumatocele ). T he surrounding ground-glass attenuation, reflecting contusions and moderate pneumothorax. (B) axial CT image in a 33-year-old man shows a paravertebral air-filled laceration ( pneumatocele ) type 2, compression shear laceration ( pneumatocele ). (C) axial CT image in a 24-year-old man shows a peripheral air-filled laceration ( pneumatocele ) subjacent to the thoracic ribs, type 3, rib penetration tear.

25. Lung laceration, type II. Coronal reformatted CT image at lung window (a) shows a lobulated paraspinal pneumatocele surrounded by ground-glass opacity (contusion) in the right lung consistent with lung laceration (type II?). On mediastinal window lung laceration is seen to have been complicated by acute pulmonary embolism.

26. Lung laceration, type IV. Axial CT image of the left lung at lung window shows a small peripheral laceration beneath a rib fracture surrounded by ground-glass opacity (lung contusion) and associated with a small ipsilateral pneumothorax.

27. Usually from ruptured alveoli Can also be from trachea, bronchi, esophagus , bowel and neck injuries

28. Linear paratracheal lucencies Air along heart border “V” sign at aortic-diaphragm junction Continuous diaphragm sign

29. Chest xray following trauma showing air outlining mediastinal structures and subcutaneous emphysema

30. V sign of neclerio

31. Hemopericardium  refers to the presence of blood within the  pericardial cavity . Can occur from blunt/penetrating/deceleration trauma. Plain radiograph enlargement of the cardiac silhouette  may be present but  chest x-rays  are insensitive and non-specific. the " straight left heart border " is an infrequent sign with low sensitivity (~40%) for hemopericardium in penetrating trauma patients. ​the  Oreo cookie sign  on lateral CXR.

32. HEMOPERICARDIUM: CT

33. Rib fractures are the most common injury in blunt chest trauma. A single rib fracture is usually not clinically significant, whereas multiple rib fractures indicate severe injury. Fractures of the first three ribs imply high-energy trauma that may be associated with injury of the brachial plexus or subclavian vessels. Fractures of the fourth up to the eighth ribs are the most common, while fractures of the last four ribs are usually associated with intra-abdominal injury.

34. Flail chest: An injury that occurs typically following a blunt trauma to the chest. When three or more ribs in a row have multiple fractures [ atleast two] within each rib, it can cause a part of your chest wall to become separated and out of sync from the rest of your chest wall. The diagnosis is clinical based on the paradoxical motion during respiration, which may result in ventilatory compromise. More than 50% of cases require surgical treatment and prolonged mechanical ventilation.

35. Coronal MIP CT image showing multiple contiguous left rib fractures.

36. Coronal (a) and sagittal (b) reconstructed CT images show fractures of three contiguous right ribs (arrows) that were associated with paradox motion of the chest during respiration. Flail chest was suspected clinically and verified on imaging.

37. Thoracic spine fractures account for up to 30% of all spine fractures. 62% of spine fractures will result in neurological deficits. The most vulnerable site is between the ninth and twelfth vertebra. The main mechanism is hyperflexion and axial loading. Sagittal and coronal MDCT reformats readily reveal even small spinal fractures. MDCT of the spine is highly indicated for spinal survey for possible fractures and determine the type of fracture. However, in the case of suspected compressive myelopathy, MRI is the method of choice.

38. Thoracic spine fracture. Coronal (a) and sagittal (b) CT reconstructed images of two different patients show fractures of the upper thoracic vertebrae.

39. Sternal fractures: 3 – 8% in blunt chest trauma. M ain mechanism: deceleration injury/direct blow to the anterior chest wall. D ifficult to detect on lateral chest radiographs . A lmost always accompanied by anterior mediastinal haemorrhage, which has a preserved fat plane with the aorta, as opposed to an anterior mediastinal haemorrhage secondary to aortic injury, which will present with a lost fat plane with the aorta.

40. Sternal fracture. Sagittal reconstructed CT image shows multiple fractures of the manubrium and the body of the sternum accompanied by extensive retrosternal haematoma.

41. Sternal fracture. Axial CT image at mediastinal window shows sternal fracture associated with retrosternal haematoma. Note the preserved fat plane with the aorta, excluding the presence of aortic injury.

42. Scapular fracture is uncommon, occurring in 3.7% of cases of blunt chest trauma. It indicates a high energy force trauma with a direct blow to the scapula or force transmitted through the humerus. Associated injuries are pneumothorax, haemothorax, clavicular fracture and injuries of the lung parenchyma, subclavian vessels, brachial plexus or spine.

43. 5% of major blunt trauma. Left clinically injured more than right 60/40. CT is a sensitive modality.

44. Signs of diaphragmatic injury: The  collar sign  (or  hourglass sign )   : a waist-like constriction of the herniating hollow viscus from the abdomen into the chest at the site of the diaphragmatic tear, which is classical for diaphragmatic rupture. The  dependent viscera sign : when a patient with a ruptured diaphragm lies supine at ct examination, the herniated viscera (bowel or solid organs) are no longer supported posteriorly by the injured diaphragm and fall to a dependent position against the posterior ribs. Segmental non-recognition of the diaphragm. Focal diaphragmatic thickening.

45. Thoracic aortic injury can result from either blunt or penetrating trauma: blunt trauma (more common) rapid deceleration ( eg. motor vehicle accident, fall from great height) crush injury penetrating trauma stab wound gunshot wound

46. Grading  Thoracic aortic injury can be graded according to the severity of injury. One grading system is  grade 1: intimal tear grade 2: intramural hematoma grade 3: pseudoaneurysm formation grade 4: free rupture

47. Signs of mediastinal hematoma Widened mediastinum Indistinct or abnormal aortic contour Deviation of trachea or NGT to the right Depression of left main bronchus Widened paraspinal stripe

48. X RAY: VASCULAR INJURY

49. Indirect signs of aortic injury: Mediastinal hematoma Periaortic fat stranding CT Angiography: 100% sensitivity and specificity Signs of mediastinal hematoma Abnormal soft tissue density around mediastinal structures Location – periaortic hematoma than isolated mediastinal hematoma remote from the aorta.

50. Signs of aortic injury: Intraluminal filling defect (intimal flap or clot) Abnormal aortic contour (mural hematoma) Pseudoaneurysm & extravasation of contrast

51. Can occur secondary to both blunt or penetrating trauma. CT is the preferred modality. Signs on CT: extraluminal gas locules in the mediastinum or abdominal cavity, adjacent to the esophagus: highly suggestive. pleural or mediastinal fluid. pneumomediastinum  or  pneumothorax . pericardial  or  pleural effusions  can be seen.

52. Herniation  of the  lung  beyond the confines of the  thoracic cage . Usually associated with rib fracture. Results in subcutaneous emphysema.

53. Causes: Usually from ruptured alveoli Can also be from trachea, bronchi, esophagus , bowel and neck injuries

54. IMAGING OF ABDOMINAL TRAUMA

55. Abdominal trauma Trauma causes I0% of deaths worldwide Blunt trauma is more common

56. Role of CT scan More accurate for solid visceral assessment Quantification of hemorrhage Assessment of retroperitoneal injuries Most sensitive and imaging modality o choice for evaluation of abdominal trauma

57. Spleen Most common injured organ in blunt trauma (40% of all solid organ injuries) CECT is the investigation of choice Integrity of organs Extent of injury / Localization of parenchymal contusions, hematoma

58. Splenic hematoma Parenchymal Subcapsular

59. Subcapsular hematoma Indents splenic parenchyma

60. Delayed splenic rupture Bleeding due to splenic injury occurring more than 48 h after blunt trauma Due to ruptures of subcapsular splenic hematomas.

61. Splenic laceration Linear low attenuation defects between high attenuation vascular spleen.

62. Splenic cleft Superiorly located Absence of hemoperitoneum

63. SENTINEL CLOT SIGN

64. Splenic infarct pyramidal wedge shaped apex pointing towards the hilum base on the splenic capsule. 

65. Imaging considerations Images should be take 50-60 seconds after contrast for uniform enhancement of the spleen

66. Contrast blush The differential diagnosis is: Active arterial extravasation Post-traumatic pseudo-aneurysm Post-traumatic AV fistula

67. American Association for the Surgery of Trauma (AAST) Grade I Subcapsular hematoma <10% capsular laceration <1 cm depth

68. Grade II Subcapsular hematoma 10-50% Parenchymal hematoma <5 cm Laceration 1-3 cm depth

69. Grade III Subcapsular hematoma >50% Intraparenchymal hematoma >5 cm Laceration >3 cm

70. Grade IV laceration hilar vessels major devascularisation (>25% of spleen)

71. Grade V Shattered spleen Hilar vascular injury with splenic devascularisation

72. Axial CECT scan shows nonenhancing spleen

73. Liver Second most commonly injured organ (20-30%) Right lobe most commonly affected (4:1) Penetrating injury

74. Hepatic Injuries Laceration (most common) Hematoma - subcapsular or intraparenchymal Active hemorrhage Major hepatic vein injury

75. Liver laceration Low attenuation defects in linear or stellate pattern.

76. Periportal tracking Blood tracking along periportal connective tissue

77. Grade I Subcapsular hematoma : <10% Laceration: capsular tear <1 cm  

78. Subcapsular hematoma: 10-50% Intraparenchymal hematoma <10 cm Laceration: 1-3 cm in parenchymal depth Grade II

79. Subcapsular hematoma: >50% Intraparenchymal hematoma >10 cm Laceration: capsular tear >3 cm parenchymal depth Grade III

80. Grade IV Parenchymal disruption involving 25-75% hepatic lobe Active bleeding

81. Grade V Laceration: parenchymal disruption involving >75% of hepatic lobe or involves >3 Couinaud’s segments (one lobe)

82. Pancreas Least commonly injured solid organ (3-12 %). Seatbelt injuries : Compression against the vertebral column. Rarely an isolated injury

83. Clinical and biochemical findings Epigastric pain Elevated serum amylase in 60 % ( 95% Negative Predictive Value)

84. CT findings 40 % of pancreatic injuries may not be visible on CT in first 12 hrs

85. laceration/transection involving neck/proximal body of pancreas

86. Grade I- Minor contusion or laceration without duct injury Grade II- Major contusion or laceration without duct injury

87. Grade III Distal pancreatic transection with duct injury

88. Grade IV :Proximal transection Grade V : Massive disruption of pancreatic head

89. Findings that may suggest pancreatic trauma Localized edema Retroperitoneal hematoma / fat infiltration. Fluid in lesser sac Thickening of anterior pararenal fascia

90. Bowel and mesentery injury Bowel and mesenteric injuries in 5% of blunt trauma MDCT is more sensitive than Clinical exam, USG, DPL

91. Direct findings –Pneumoperitoneum or pneumo-retroperitoneum

92. Direct findings Contrast extravastation Interloop fluid Bowel wall discontinuity

93. Less common signs Focal bowel wall thickening greater than 3 mm Mesenteric infiltration, thickening Abnormal bowel wall enhancement

94. Shock bowel Hypoperfusion state

95. Mesenteric injury Signs Contrast extravasation Beaded mesenteric vessels Hematoma Infiltration

96. Vascular injury – CT findings IVC injuries lumen is irregular and compressed by hematoma Active contrast extravasation.

97. Aortic injuries Contrast extravasation Large psoas or mesenteric hemorrhage, pseudo-aneurysm. Pelvic vasculature injuries are associated with pelvic fractures.

98. Imaging of Renal Trauma Computed tomography (CT) is the modality of choice Injury to the kidney is seen in approximately 8%– 10% of patients with blunt or penetrating abdominal injuries

99. Subcapsular hematoma (category I) Crescent shaped hyperdensity , located in the periphery of the kidney

100. Laceration Hypodense , irregularly linear areas, typically distributed along the vessels and filled with blood. They are best analyzed at arterial phase Superficial (<1 cm from the renal cortex) Deep (>1 cm from the renal cortex)

101. Simple renal laceration (category I)

102. Major renal laceration without involvementof the collecting system (category II <1 cm)

103. Major renal laceration involving the collecting system (category II)

104. Multiple renal lacerations (category III >1 cm)

105. Shattered kidney (category III)

106. Segmental renal infarction (category II)

107. Traumatic occlusion of the main renal artery (category III)

108. Active arterial extravasation (category III)

109. Vein Pedicle Injury Incomplete or absent opacification of the renal vein Persistent nephrogram Reduction in excretion Nephromegaly

110. Laceration of the renal vein (category III)

111. Urinoma / Urohematoma Presence of a more or less significant breach of the collecting tube system, with urine escape reflected by extravasation of contrast medium on delayed imaging, in an extrarenal location

112. Avulsion of the ureteropelvic junction (category IV)