Brain imaging is important in trauma to identify injuries from primary impact and secondary complications. CT is best for acute trauma to detect fractures and hemorrhages while MRI is more sensitive for diffuse injuries. Common primary injuries seen include fractures, contusions, hematomas, shearing injuries and hemorrhages in various locations. Secondary complications can include swelling, infection and herniations putting pressure on vessels.

1. Brain Imaging in TraumaBrain Imaging in Trauma

2. Level Of ConsciousnessLevel Of Consciousness
Glasgow Coma Scale
Eye Opening Best Verbal Best Motor
Spontaneous 4 Oriented 5 Obeys Command
6
To Voice 3 Confused 4 Localizes 5
To Pain 2 Inappropriate 3 Withdraws 4
None 1 Incomprehensible 2 Flexion 3
None 1 Extension 2
None 1

3. Primary Brain InjuryPrimary Brain Injury

4. Classification of TBIClassification of TBI
Primary
◦ Injury to scalp, skull fracture
◦ Surface contusion/laceration
◦ Intracranial hematoma
◦ Diffuse axonal injury, diffuse vascular injury
Secondary
◦ Hypoxia-ischemia, swelling/edema, raised intracranial
pressure
◦ Meningitis/abscess

5. IMAGINGTECHNIQUEIMAGINGTECHNIQUE
CT without contrast is the modality of
choice in acute trauma (fast, available,
sensitive to acute subarachnoid
hemorrhage and skull fractures)
MRI is useful in non-acute head trauma
(higher sensitivity than CT for cortical
contusions, diffuse axonal injury, posterior
fossa abnormalities)

6. Extraaxial fluid collectionsExtraaxial fluid collections
Subarachnoid hemorrhage(SAH)
Subdural hematoma(SDH)
Epidural hematoma
Subdural hygroma
Intraventricular hemorrhage

8. EPIDURAL HEMATOMAEPIDURAL HEMATOMA
Located between the skull and
periosteum
Due to laceration of the middle
meningeal artery or dural veins
Can cross dural reflections but is limited
by suture lines
Lentiform shape (but concave shape in
SDH)

11. SUBDURAL HEMATOMASUBDURAL HEMATOMA
Occurs between the dura and arachnoid
Can cross the sutures but not the dural
reflections
Due to disruption of the bridging cortical
veins
Hypodense(hyperacute, chronic),
isodense(subacute), hyperdense(acute)

12. W=33 L=41

15. Subarachnoid hemorrageSubarachnoid hemorrage
Can originate from direct vessel injury,
contused cortex or intraventricular
hemorrhage.
Look in the interpeduncular cistern and
Sylvian fissure
Usually focal (but diffuse from aneurysm)
Can lead to communicating hydrocephalus

19. Intraventricular hemorrhageIntraventricular hemorrhage
Most commonly due to rupture of
subependymal vessels
Can occur from reflux of SAH or
contiguous extension of an intracerebral
hemorrhage
Look for blood-cerebrospinal fluid level
in occipital horns

21. INTRA-AXIAL INJURYINTRA-AXIAL INJURY
Surface contusion/laceration
Intraparenchymal hematoma
White matter shearing injury/diffuse
axonal injury
Post-traumatic infarction
Brainstem injury

22. CONTUSION/LACERATIONSCONTUSION/LACERATIONS
Most common source of traumatic SAH
Contusion: must involve the superficial gray
matter
Laceration: contusion + tear of pia-arachnoid
Affects the crests of gyri
Hemorrhage present ½ cases and occur at right
angles to the cortical surface
Located near the irregular bony contours: poles
of frontal lobes, temporal lobes, inferior
cerebellar hemispheres

24. Intraparenchymal hematomaIntraparenchymal hematoma
Focal collections of blood that most
commonly arise from shear-strain injury
to intraparenchymal vessels.
Usually located in the frontotemporal
white matter or basal ganglia
Hematoma within normal brain
DDx: DAI, hemorrhagic contusion

26. DIFFUSE AXONAL INJURYDIFFUSE AXONAL INJURY
Rarely detected on CT ( 20% of DAI
lesions are hemorrhagic)
MRI:T1,T2,T2 GRE, SWI

27. DAIDAI
Due to acceleration/deceleration to
whtie matter + hypoxia
Patients have severe LOC at impact
Grade 1: axonal damage in WM only -67%
Grade 2:WM + corpus callosum
(posterior > anterior) – 21%
Grade 3:WM + CC + brainstem

28. DAIDAI
Hours:
◦ hemorrhages and tissue tears
◦ Axonal swellings
◦ Axonal bulbs
Days/weeks: clusters of microglia and
macrophages, astrocytosis
Months/years:Wallerian degeneration

31. Axial FLAIR imagesAxial FLAIR images

32. AXIAL FLAIRAXIAL FLAIR

33. T2 * & SWIT2 * & SWI

34. BRAINSTEM INJURYBRAINSTEM INJURY
By direct or indirect forces
Most commonly associated with DAI
Involves the dorsolateral midbrain and upper
pons and is usually hemorrhagic
Duret hemorrhage is an example of indirect
damage: tearing of the pontine perforators
leading to hemorrhage in the setting
transtentorial herniation
<20% of brainstem lesions are seen on CT

40. SUBFALCIAL HERNIATIONSUBFALCIAL HERNIATION
Subfalcial: displacement of the cingulate
gyrus under the free edge of the falx
along with the pericallosal arteries.
Can lead to anterior cerebral artery
infarction

44. UNCAL HERNIATIONUNCAL HERNIATION
Displacement of the medial temporal lobe
through the tentorial notch
Displacement of the midbrain
Effacement of the suprasellar cistern
Displacement of the contralateral cerebral
peduncle against the tentorium
Widening of the ipsilateral cerebello pontine
angle
Compression of the posterior cerebral artery

46. DuretDuret

47. Kernohan - false ipsilateralKernohan - false ipsilateral

49. UPWARD HERNIATIONUPWARD HERNIATION
Due to posterior fossa mass causing
superior displacement of the vermis
through the tentorial incisura
Compression of the 4th
ventricle and
effacement of the quadrigeminal plate
cistern.
Compression of the superior cerebellar
artery & pca

51. TONSILLAR HERNIATIONTONSILLAR HERNIATION
Inferior displacement of the cerebellar
tonsils through the foramen magnum
Can lead to posterior cerebellar artery
infarction

53. Skull FracturesSkull Fractures
Thin skull #’s common place.
Risk of # associated intracranial injuries?
CT to R/o
1. Open
2. Closed
3. Comminuted
4. Diastatic
5. Depressed

54. SIGNIFICANT SKULL FRACTURESSIGNIFICANT SKULL FRACTURES
“Depressed”: inner table is depressed by
the thickness of the skull.
Overlie major venous sinus, motor
cortex, middle meningeal artery
Pass through sinuses
Look for sutural diastasis (lambdoid)

57. TEMPORAL BONE FRACTURESTEMPORAL BONE FRACTURES
Look for opacification of the mastoid
Longitudinal: 70%, parallel to long axis of
petrous bone, conductive hearing loss
(from ossicular dislocation), facial nerve
paralysis (20%)
Transverse: 20%, sensorineural hearing loss,
facial nerve paralysis (50%)
Complex
Complications: meningitis, abscess

59. SCALP INJURYSCALP INJURY

60. SCALP INJURYSCALP INJURY
Cephalohematoma: blood between the bone
and periosteum. Cannot cross the suture lines.
Subgaleal hematoma: blood between the
periosteum and aponeurosis. Can cross the
suture lines.
Caput Succ: swelling across the midline with
scalp moulding. Resolves spontaneously.

61. POSTTRAUMATIC SEQUELAEPOSTTRAUMATIC SEQUELAE
Carotid-cavernous fistula(CCF)
Dissection/pseudoaneurysm
Infarction
Atrophy/encephalomalacia
Infection
Leptomeningeal cyst