Diagnostic Imaging of Cerebral Trauma

1. C.N.S.
Cerebral Trauma

2. Mohamed Zaitoun
Assistant Lecturer-Diagnostic Radiology
Department , Zagazig University Hospitals
Egypt
FINR (Fellowship of Interventional
Neuroradiology)-Switzerland
zaitoun82@gmail.com

5. Knowing as much as
possible about your enemy
precedes successful battle
and learning about the
disease process precedes
successful management

6. Cerebral Trauma
(i) Primary Effects
(ii) Secondary Effects
(iii) Delayed Effects

7. (i) Primary Effects :
a) Fracture
b) Extra-Axial Hemorrhage
c) Intra-Axial Injury

8. a) Fracture :
1-Linear fractures (common)
2-Complex fractures (diastatic, stellate &
depressed) tends to occur with mechanisms
involving greater degrees of force
3-Skull base fractures may be occult (2ry clues are
fluid in the sphenoid sinus or mastoid air cells
and pneumocephalus)
4-Facial nerve palsy or ossicular disruption in
temporal fractures

9. CT scan of 35-year-old male with recent motor vehicle accident
demonstrating longitudinal fracture of the right petrous bone (thin arrow)
that extends into the skull base (thick arrow)

10. Axial non-contrast CT scan at the time of initial injury showed a diastatic left
parietal fracture and an underlying hemorrhagic brain contusion

11. b) Extra-Axial Hemorrhage :
1-Epidural Hematoma
2-Subdural Hematoma
3-Subarachnoid Hemorrhage
4-Intraventricular Hemorrhage
5-Subdural Hygroma

12. 1-Epidural Hematoma : (See Stroke)
a) Etiology
b) Radiographic Features

13. a) Etiology :
-Usually arterial bleed (middle meningeal artery)
-95% are associated with fractures (classically
caused by fracture of the squamous portion of
the temporal bone)

14. b) Radiographic Features :
-95% are unilateral , temporoparietal
-Biconvex , lenticular shape
-Does not cross suture lines (as the dura is
tightly adherent to the cranium)
-May cross dural reflections (falx tentorium) , in
contradistinction to subdural hematoma
-Commonly associated with skull fractures
-Heterogeneity predicts rapid expansion of
EDH , with areas of low density representing
active bleeding
-Staging of hematoma (See Intracerebral
Hematoma)

15. Left parietal epidural hematoma, (A) T1, (B) T2, hematoma shows high signal
on both images, which is consistent with extracellular methemoglobin

16. 2-Subdural Hematoma : (See Stroke)
a) Etiology
b) Radiographic Features
c) Differential Diagnosis

17. a) Etiology :
-Caused by traumatic tear of bridging veins
(rarely arteries)
-In contradistinction to EDH , there is no
consistent relationship to the presence of skull
fractures
-Common in infants (child abuse , 80% are
bilateral or interhemispheric) and elderly
patients (20% are bilateral)

18. b) Radiographic Features :
-95 % supratentorial
-Crescentic shape along brain surface
-Crosses suture lines (since it is underneath the dura ,
the hematoma can extend across the cranial sutures)
-Does not cross dural reflections (falx , tentorium)
-Staging of hematoma (See Intracerebral Hematoma)
-An isodense subdural hematoma is isoattenuating to
gray matter , this occurs in the subacute phase (1-3
weeks after the initial injury) , 3 important clues
alerting to the presence of an isodense subdural are :
1-Increased mass effect
2-White matter buckling
3-Apparently thickened cortex

19. CT of an 87-year-old female status post fall showing a large subdural
hematoma along the left cerebral convexity with significant midline shift
and effacement of the left lateral ventricle

20. CT of an 80-year-old female status post fall showing a large left subdural
hematoma in addition to substantial subarachnoid hemorrhage (arrows)

21. c) Differential Diagnosis :
EDH SDH
1-Incidence >5%of TBIs 10-20%
2-Cause Fracture Tear of cortical veins
3-Location Between skull & dura Between dura &
arachnoid
4-Shape Biconvex Cresentic
5-CT 70%hyperintense , 30
% isointense
Variable depending on
age
6-T1 Isointense Variable depending on
age

22. 3-Subarachnoid Hemorrhage : (See
Subarachnoid hemorrhage)
-Post traumatic SAH usually low volume
scattered bleeds ; peripheral distribution
-Trauma is the most common cause of SAH
while aneurysm rupture is the most common
cause of non-traumatic SAH

23. Traumatic SAH , high density blood (arrowheads) fills the sulci over the
right cerebral convexity in this subarachnoid hemorrhage

24. 4-Intraventricular Hemorrhage :
-Can occur due to tearing of subependymal
veins or from direct extension of subarachnoid
or intraparenchymal hematoma
-Patients with intraventricular hemorrhage are
at increased risk of developing
noncommunicating hydrocephalus due to
ependymal scarring which may obstruct the
cerebral aqueduct

27. 5-Subdural Hygroma :
1-Etiology
2-Radiographic Features

28. 1-Etiology :
-Accumulation of CSF in subdural space after
traumatic arachnoid tear

29. 2-Radiographic Features :
-CSF density
-Does not extend into sulci
-Vessels cross through lesion
-Main considerations in differential diagnosis :
1-Chronic SDH
2-Focal atrophy with widened subarachnoid
space

31. c) Intra-Axial Injury :
1-Coritcal Contusion
2-Intraparenchymal Hematoma
3-Diffuse Axonal Injury

32. 1-Contusions :
a) Etiology
b) Location
c) Radiographic Features

33. a) Etiology :
-Focal hemorrhage / edema in gyri secondary to
traumatic contact of the cortical surface of the
brain against the rough inner table of the skull

34. b) Location :
-Characteristic locations are :
1-Anterior temporal lobes , 50 %
2-Inferior frontal lobes , 30 % (impact against
bony anterior walls of anterior & middle
cranial fossae)
3-Parasagittal hemisphere
4-Brainstem

35. c) Radiographic Features :
-Initial CT is often normal , later on , low density lesions
with or without blood in them develop
-Lesions evolve with time , delayed hemorrhage in 20%
-Larger mixed attenuation (CT) or signal (MRI) intra-
axial lesions
-A subacute cortical contusion may show ring
enhancement and should be considered in the
differential of a ring enhancing lesion if there is a
history of trauma
-Chronic contusion appears an encephalomalacia on CT
, MRI is more specific showing peripheral
hemosiderin deposition as hypointense on T2 and
blooming artifact on gradient echo sequences

36. Hemorrhagic progression of a contusion (HPC), (A and B) A 21-year-old
female pedestrian struck by a motor vehicle had a computed tomography
(CT) examination performed within 2h of trauma, and a repeat CT
examination 6h later, note the expansion of the right frontal contusion

37. Acute brain contusion, axial CT obtained in a patient immediately after a
high-speed motor vehicle accident demonstrates a large, right frontal
contusion with hemorrhage and surrounding edema, a smaller, subtle,
right temporal cortical contusion (short arrow) is noted, as well as a small,
left frontal subdural hematoma (long arrow)

38. Left frontal fracture with pneumocephalus, brain swelling, and
small hemorrhagic contusions in the basal frontal cortex

39. Axial CT obtained immediately after blunt trauma to the left convexity of the
skull resulted in severe swelling of the entire left cerebral hemisphere
with loss of the gyral pattern secondary to edema, a small collection of
subarachnoid blood is present (up arrow), the right hemisphere shows
contrecoup gliding contusions (down arrows)

40. CT scan shows bifrontal contusions following severe head
trauma (arrows)

41. Evolution of an acute brain contusion, (A) Axial CT obtained immediately following
severe blunt trauma to the head shows a small, left frontal epidural hematoma
(arrow), extensive subgaleal bicranial hematomas are seen, (B) Companion CT
obtained 6 days after trauma shows the small, left frontal epidural hematoma
(long arrow) and smaller areas of subgaleal bicranial hematomas, note that the
previously isoattenuating contusion in the right posterior temporal area is now
evident (short arrows in B)

42. Resolution of a brain contusion, (A) Axial CT scan obtained on day 1 after a high-speed
motor vehicle accident shows subtle evidence of bifrontal hemorrhagic contusions
(arrows), (B) Axial CT scan obtained on day 2 shows increased hemorrhage within
the inferior frontal cortex bilaterally (arrows), (C) Axial CT scan obtained on day 14
shows resolution of the bright blood (upper arrows) and residual areas of dark
edema in both frontal lobes and a subtle area throughout the right temporal lobe
(lower arrows)

43. Subacute contusion , (a) CT, (b) CT+C

44. T2 FLAIR SWI

45. 2-Intraparenchymal Hematoma :
-Traumatic intraparenchymal hematoma can
occur in various locations ranging from
cortical contusions to basal ganglia
hemorrhage (due to shearing of
lenticulostriate vessels)
-Similar to cortical contusion, a subacute
intraparenchymal hematoma may show ring
enhancement

46. MRI of 66-year-old male after a motor vehicle accident showing a large right frontal
intraparenchymal hemorrhage on the FLAIR (left image) and T2 (right image)
sequences, the FLARE images shows diffuse, heterogeneous increased signal
intensity consistent with evolving blood products with surrounding edema in the
frontal lobe

47. 3-Diffuse Axonal Injury (Traumatic Axonal
Injury T.A.I., Axonal Shear Injury) :
a) Etiology
b) Location
c) Grading
d) Radiographic Features

48. a) Etiology :
-DAI is due to axonal disruption from shearing
forces of acceleration / deceleration
-It is most commonly seen in severe head injury
-Loss of consciousness occurs at time of injury
-The term traumatic axonal injury (TAI) has
recently been introduced as this injury pattern
is thought to be multifocal rather than diffuse

49. b) Location :
1-Grey-white junction
2-Corpus callosum
3-Dorsolateral midbrain

50. c) Grading :
-The higher the grade , the worse the prognosis :
1-Grade I DAI :
-Involves only the gray-white junctions
2-Grade II DAI :
-Involves the corpus callosum
3-Grade III DAI (most severe) :
-Involves the dorsolateral midbrain

51. d) Radiographic Features :
1-CT :
-Initial CT is often normal
-Scattered low attenuation lesions at grey-white
junction (high attenuation if hemorrhagic)
2-MRI :
-Gradient echo T2 is the most sensitive
sequence to detect hemorrhagic shear injuries
also (however not all DAI is hemorrhagic)
-FALIR is most sensitive for nonhemorrhagic DAI
(multifocal T2 bright lesions)
-Diffusion sequence show restricted diffusion in
acute DAI due to cytotoxic edema and cell
swelling

53. DAI , axial GRE shows several foci of susceptibility effect along the left high
convexity representing punctate hemorrhagic foci of DAI (arrows)

54. Diffuse axonal injury, axial susceptibility weighted images show multiple small
hypointense foci of hemorrhage within the right temporal lobe and
midbrain (A), splenium of the corpus callosum (B) and right parietal lobe
(C), which are usually hardly visible on other MR sequences

55. Axonal Shear Injury

56. Axonal Shear Injury

57. (ii) Secondary Effects :
1-Cerebral Herniation
2-Diffuse Cerebral Edema
3-Arterial Dissection

58. 1-Cerebral Herniation :
a) Definition
b) Types
c) Radiographic Features

59. a) Definition :
-Mechanical displacement of brain secondary to
mass effect
-Herniation may be due to a mass lesion (such as
neoplasm or hematoma) or may be due to
edema secondary to a large stroke , because
the volume of the posterior fossa is especially
limited , cerebellar infarcts are prone to
herniation

60. b) Types :
1-Subfalcine herniation
2-Descending Transtentorial (uncal) herniation
3-Ascending Transtentorial herniation
4-Tonsillar herniation

64. c) Radiographic Features :
(i) Subfalcine Herniation :
-The most common intracranial herniation
pattern , characterized by displacement of the
brain under the free edge of the falx cerebri
due to raised intracranial pressure
-Cingulate gyrus slips under free margin of falx
cerebri
-Compression of ipsilateral ventricle
-Entrapment and enlargement of contralateral
ventricle (may result from foramen of Monro
obstruction)
-May result in ACA ischemia (by compression of
the ACA against the falx)

66. (ii) Descending Transtentorial (uncal) Herniation:
-Second most common
-A hemispheric mass initially produces subfalcine
herniation , as the mass effect increases , the uncus
of the temporal lobe is pushed medially , begins to
encroach on the suprasellar cistern , hippocampus
follows , hippocampus effaces the ipsilateral
quadrigeminal cistern >> both the uncus &
hippocampus herniate inferiorly through the
tentorial incisura
-Enlargement of ipsilateral CPA cistern

67. -Duret hemorrhage (anterior midbrain) , due to
shearing of perforating vessels due to downward
force on the brainstem
-Compression of the contralateral cerebral peduncle
against Kernohan's notch causes a hemiparesis
ipsilateral to the herniated side
-PCA ischemia : occipital lobe , thalami , midbrain
-The ipsilateral cranial nerve (occulomotor nerve) may
be compressed leading to pupillary dilatation & CN III
palsy (eye is down & out)

69. (iii) Ascending Transtentorial herniation :
-Is the superior transtentorial herniation of the
cerebellar vermis due to posterior fossa mass
effect
-The main complication of upward transtentorial
herniation is obstructive hydrocephalus from
aqueductal compression
-Loss of quadrigeminal cistern

71. (iv) Tonsillar herniation :
-Cerebellar tonsils pushed inferiorly through the
foramen magnum causes compression of the
medulla
-Compression of medullary respiratory centers is
often fatal

73. 2-Diffuse Cerebral Edema :
a) Etiology
b) Radiographic Features

74. a) Etiology :
-Massive brain swelling and intracranial hypertension
secondary to dysfunction of cerebrovascular
autoregulation and alterations of the blood brain
barrier
-Underlying causes include ischemia and severe trauma
-Ischemia may be primary (e.g. anoxic , drowning) or
secondary to other brain injuries (e.g. large SDH) and
may be followed by infarction
-More common in children (Hypoxic Ischemic Injury)
-High morbidity / mortality rates

75. b) Radiographic Features :
-Findings develop 24 to 48 hours after injury
-Effacement of sulci and basilar cisterns
-Loss of perimesencephalic cisterns (hallmark)
-Loss of GM / WM interface (cerebral edema)
-White cerebellum sign : diffuse decrease in
density of the supratentorial brain
parenchyma with relatively increased
attenuation of the thalami , brainstem and
cerebellum

76. White cerebellum sign

77. CT without contrast shows the reversal sign with diffuse and extensive hypodensity of
the cerebral cortices and relative sparing of the bas al ganglia and cerebellum

78. 3-Arterial Dissection :
a) Etiology
b) Location
c) Radiographic Features
d) Complications

79. a) Etiology :
-Blood splits the media , creating a false lumen that
dissects the arterial wall
-Causes :
1-Spontaneous or with minimal trauma (strain , sports)
2-Trauma
3-Hypertension
4-Vasculopathy (FMD , Marfan syndrome)
5-Migraine headache
6-Drug abuse

80. b) Location :
-carotid artery (starts 2 cm distal to bulb and
spares bulb) > ICA (petrous canal) > vertebral
artery > others

81. c) Radiographic Features :
1-CTA is preferred first study of choice, see
intimal flap and caliber change
2-MRI / MRA :
-T1 bright hematoma in vessel wall (sequence:
T1 with fat saturation ), must be interpreted in
conjunction with MRA
-MRA string sign

82. Curved reformatted image from contrast-enhanced CT angiography shows
the cervical ICA, cervical ICA dissection affects the ICA distal to the carotid
bulb (white arrowhead) and tends not to extend beyond its entry into the
petrous bone (black arrowhead)

83. Axial fat-saturated T1 shows slightly hyperintense wall thickening of the left
ICA (arrowheads), a finding consistent with an early subacute intramural
hematoma (methemoglobin phase)

84. Subacute dissection of the left ICA in a 55-year-old man with transient ischemia, (a, b) Axial T1
obtained with fat saturation (a obtained at a higher level than b) show a narrowed eccentric
flow void (arrowhead) surrounded by a crescent-shaped circumferential subacute intramural
hematoma that expands the vessel diameter, the hematoma spirals around the vessel
lumen, (c) 3D MIP image from contrast-enhanced MR angiography shows narrowing and
smooth irregularities of the ICA lumen distal to the carotid bulb, note the kinking of the ICA
above the dissection

85. Axial T1 fat-suppressed demonstrates a crescent sign (arrow) around the
right ICA

86. Long-segment high-grade stenosis (string sign) identified on CTA, which appeared
occluded on MR imaging/MRA, (A and B), Curved planar reformatted images of the
left ICA demonstrate flamelike tapering of the proximal vessel with wall thickening
and long-segment high-grade stenosis (arrow), (C), Axial plane from CTA shows the
tiny residual lumen of the vessel (arrow), (D), Contrast-enhanced MRA acquired on
the same day demonstrates apparent occlusion just distal to the carotid
bifurcation (arrow)

87. Right vertebral artery dissection with a pseudoaneurysm seen on CTA, which is not visualized on
MR imaging/MRA, (A), Curved planar reformatted image from CTA of the distal right
vertebral artery demonstrates irregularity (arrow) as well as a small distal pseudoaneurysm,
(B), axial CTA source image shows contrast within the true lumen and the pseudoaneurysm
anteriorly (arrow), (C), Contrast-enhanced MRA demonstrates the irregularity associated
with the dissection, but not the pseudoaneurysm, (D), 2D time-of-flight MRA depicts the
narrowed true lumen but does not show the pseudoaneurysm, presumably due to saturation
of slow-flowing blood

88. Dissection of the left cervical ICA in a 46-year-old woman, (a) Axial image
from CT angiography shows enlargement of the overall vessel diameter
(arrows) and a narrowed eccentric lumen (arrowhead), (b) Volume-
rendered image from CT angiography shows a long tapered stenosis that
begins distal to the carotid bulb (the string sign)

89. 3-Conventional Angiography :
-May establish the diagnosis and fully elucidate
abnormal flow patterns
-Long segment fusiform narrowing of affected
artery

90. Angiographic images of the right ICA (A) and right VA (B), curved planar
reformat images from the CTA study of the right ICA (C) and right VA (D),
both demonstrate vessel wall irregularity, mild luminal narrowing, and
pseudoaneurysm of the right ICA (arrows), (E), Corresponding MIP image
from contrast-enhanced MRA shows both dissections (arrows), but with
less clear depiction than that on CTA, (F), Axial T1 fat-suppressed
demonstrates a crescent sign consistent with intramural hematoma
around both the right ICA and VA (arrows)

91. d) Complications :
1-Thrombosis
2-Emboli and infarction
3-Intramural hemorrhage
4-False aneurysm

92. (iii) Delayed Effects :
1-Atrophy
2-CSF Leak
3-AVF
4-Pseudoaneurysm
5-Leptomeningeal Cyst

93. 1-Atrophy :
a) Focal (following contusion)
b) Generalized (following DAI or large extra-axial
hematomas which required surgical evacuation)
2-CSF Leak :
-Secondary to fractures of frontal sinus , anterior
cranial fossa , sphenoid sinus , temporal bone
(secondary meningitis)

94. (A,B), Left frontal lobe contusion with local atrophy, the first (A) and second
(B) MR images were obtained 390 days apart
(C,D), Left parietal lesion and increased sulcal prominence, the first (C) and
second (D) MR images were 118 days apart

95. 3-Arteriovenous Fistula (AVF) :
-Direct Caroticocavernous fistula (See Vascular
malformations)
4-Pseudoaneurysm :
-Following arterial wall tear

96. CTA shows a 10mm pseudoaneurysm in the right common
carotid artery (black arrow)

97. Digital subtraction angiography of left internal carotid artery showing the
pseudoaneurysm medial to ICA filling up with contrast with narrowed and
irregular lumen of ICA (arrow)

98. 5-Leptomeningeal Cyst :
-Dura trapped within the fracture line
-CSF pulsation prevents fracture healing leading
to growing fracture

99. Axial CT head shows expanded intradiploic space (CSF density) of
the right temporal bone with resultant gross thinning of the
tables

100. Axial non-contrast CT scan 7 weeks after trauma, showed an enlarging
fracture with a cystic mass advancing through the bone defect,
characteristic of a leptomeningeal cyst

101. CT shows growing skull fracture with underlying parenchymal injury with
subdural collection and leptomeningeal cyst