1. بسم الله الرحمن الرحيم

2. BRAIN CT IN EMERGENCY

3. Lecture Objectives: Normal anatomy of brain CT Trumatic brain injury
Subarachnoid hemorrhage
Intraparenchymal hemorrhage
Stroke
Brain edema
Cerebral herniation

6. NON- ENHANCED CT STUDY

7. CONTRAST ENHANCED CT STUDY

8. A. Orbit
B. Sphenoid Sinus
C. Temporal Lobe
D.Externa Auditory Canal
E. Mastoid Air Cells
F. Cerebellar Hemisphere

9. A. Anterior Horn of the Lateral Ventricle
B. Caudate Nucleus
C. Anterior Limb of the Internal Capsule
D. Putamen and Globus Pallidus
E. Posterior Limb of the Internal Capsule
F. Third Ventricle
G. Quadrigeminal Plate Cistern
H. Cerebellar Vermis
I. Occipital Lobe

10. A. Falx Cerebri
B. Frontal Lobe
C. Body of the Lateral Ventricle
D. Splenium of the Corpus Callosum
E. Parietal Lobe
F. Occipital Lobe
G. Superior Sagittal Sinus

11. A. Falx Cerebri
B. Sulcus
C. Gyrus
D. Superior Sagittal Sinus

12. CT SCAN..
Bone window
fracture

13. BRAIN MRI STUDY
T1WI
FLAIR
T2WI

14. CT SCAN.. Contrast enhanced CT Contrast enhanced CT:
IV injection of contrast medium is often given because the abnormality not seen in pre contrast scans may be rendered visible following contrast enhancement (consequence of breakdown of blood brain barrier allowing contrast to enter the lesion particularly in neoplasm, infection, inflammation and certain stage of ischemia).
Also it is helpful in demonstrating blood vessels
MCA
ACA
Basilar artery
Straight sinus
Superior sagittal sinus
Contrast enhanced CT

15. CT SCAN.. Computer reconstructions
can in selected circumstances be made from the axial sections which then provide images in coronal or sagittal planes.
Sagittal reconstruction
Coronal reconstruction

16. CT SCAN..
CTA
CT angiography is helpful in diagnosis of vascular diseases and abnormalities such as stenosis, occlusion or vascular malformation
Occlusion of left middle cerebral artery

17. Computed Tomographic Cerebral Venography (CTV)
Can be reliably assess intracranial venous system
Comparable to MR angiographic techniques
Rapid and readily available
Avoids many patient contraindications that may prevent MR evaluation
Using iodinated contrast material, requires complex post processing to remove bony structures from reconstructed images

18. CT SCAN..
CT PERFUSION
cerebral blood volume
cerebral blood flow

19. CT SCAN..
CT PERFUSION
In acute stroke, very early cranial CT may be normal. Perfusion CT shows great promise in refining the selection of patients suitable for thrombolysis, as it can accurately determine infarct core from potentially salvageable ischaemic penumbra.
Some cerebral tumours are associated with angiogenesis and a breakdown of the blood-brain barrier. Angiogenesis can be detected as an increase in flow and volume parameters, and blood-brain barrier breakdown can be quantified as contrast accumulates in the interstitial space. Such aggressive features can distinguish malignant from benign tumours when standard imaging may not.

20. 20

21. Traumatic brain injury:
Secondary:
- Brain herniation
- Traumatic ischemia
- Diffuse cerebral edema
- Hypoxic brain injury
Primary:
Extraaxial hemorrhage:
- Epidural hematoma
- Subdural hematoma
- Subarachnoid hemorrhage
Intraaxial lesions:
- Diffuse axonal injury
- Cortical contusion
- Deep gray matter injury
- Brainstem injury
- IVH

22. Epidural hematoma 90% is arterial (middle meningeal artery)
Temporoparietal
Biconvex, lenticular
Does not cross suture lines, crosses dural reflections
Commonly associated with skull fractures

24. CT SCAN.. Bone window Brain window fracture
Acute extradural hemorrhage
Bone window
Brain window
fracture
The window settings are selected for the brain, but may be altered to shows the bones.

25. Subdural hematoma Tear of cortical bridging veins
Cresentric along the brain surface
Crosses suture lines, does not cross dural reflections
Common in infants (child abuse) and in the elderly

30. Subarachnoid hemorrhage
Hyperdense CSF in the basal cisterns, sylvian fissure and subarachnoid space
Aneurysm rupture is the most common cause in non trauma patient
Patients present with the worst headache of their life

31. Subarachnoid hemorrhage

32. Subarachnoid hemorrhage
The pattern of hemorrhage may give a clue to the location of the ruptured aneurysm:
A-com aneurysm ⇒ interhemispheric fissure
P-com aneurysm ⇒ ipsilateral basal cisterns
MCA trifurcation ⇒ sylvian fissure
Basilar tip ⇒ interpeduncular cistern, intraventricular
PICA ⇒ posterior fossa cisterns, intraventricular

33. Pseudo-subarachnoid hemorrhage
Symmetric increased density in the basal cisterns with no sulcal density
30-40 HU
Assoaciated with generalized brain edema
History of recent cardiopulmonary resuscitation

35. Diffuse axonal injury
Axonal disruption from shearing forces of acceleration/deceleration
Patients are unconscious with severe head injury
Common locations:
- Lobar gray/white matter junction
- Corpus callosum
- Dorsolateral brain stem

36. Diffuse axonal injury
Initial CT is often normal. Petechial hemorrhage develops later.
Susceptibility-sensitive, gradient-echo MR sequences are most sensitive for detecting hemorrhagic shear injuries.

37. Diffuse axonal injury

39. Cortical contusions
Focal hemorrhage/edema secondary to brain impacting on bone or dura
Located 180 degrees from the site of direct impact (contrecoup)
Characteristic locations:
- Anterior temporal
- Inferior frontal
- Parasagittal hemisphere
- Splenium of the corpus callosum
- Brainstem

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42. Intra ventricular hemorrhage

43. Intraparenchymal hemorrhage
Causes:
- Hypertension
- Amyloid angiopathy
- Vascular malformations
- Coagulopathy
- Trauma
- Drug induced
- Tumor hemorrhage

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46. Stroke Types: - Ischemic stroke - Hemorrhagic stroke
- Venous occlusion

47. Ischemic stroke Imaging findings:
Nonenhanced CT is the initial investigation of choice
Exclude hemorrhage and underlying mass or AVM
Imaging findings:
Normal in early stroke
Hyperdense clot in the affected artery
Insular ribbon sign
Sulcal effacement
Cytotoxic edema develops by 6 hours

48. Ischemic stroke
Acute infarction cannot be excluded on the basis of a negative CT.
Diffusion weighted MRI is most sensitive for detecting acute infarction
Hemorrhagic transformation can develop in the subacute stage (gradient echo MRI)

51. Insular Ribbon Sign

52. 1st Day

53. 2nd Day

56. Old CT
Recent CT

58. PICA Infarction

59. Dense basilar artery (arrow)
Dense basilar artery (arrow). Compare this to the normal internal carotid artery (arrowhead).

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66. Cerebral Venous Thrombosis
Can involve the: dural sinuses, cortical veins or deep cerebral veins

67. Venous occlusion

68. Spectrum of CT findings
10-30% of cases of CVT are negative on either unenhanced or
contrast-enhanced CT
Highly suspicious cases should be furtherly evaluated with CT venography or MRI

69. Unenhanced CT:
Direct signs of CVT “dense clot sign” seen only on 30% of cases.
Diffuse brain edema 20-50%

70. Venous infarction: Unenhanced CT:
Not conforming to a major arterial vascular territory,
Involving subcortical region
solitary or multiple isolated lesions
Hemorrhagic or non hemorrhagic.

71. Unenhanced CT:
Bilateral infarction at thalami, basal ganglia and internal capsules suggesting deep venous thrombosis

73. Contrast-Enenhanced CT:
Direct evidence of CVT “Empty Delta Sign”
Indirect evidence of CVT may be seen as contrast enhancement of the adjacent dura or vascular engorgement

74. CT Venography:
Allow direct visualization of thrombus as filling defect

75. 1st day
2nd day

80. Diagnostic Pitfalls
Pseudodelta sign

81. Normal variant of dense sinus

82. Unenhanced CT scans show subdural hemorrhage along falx and tentorium cerebelli, simulating sagittal and transverse sinus thrombosis.

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84. Brain edema Cytotoxic: Vasogenic: - Due to cellular swelling
- In the setting of cerebral ischemia
- Involves both gray and white matter
Vasogenic:
- Disruption of BBB and leakage of fluid outside capillaries
- Associated with tumors and abscesses
- Involves only the white matter

85. Brain edema
Cytotoxic
Vasogenic

86. Diffuse brain edema Causes include: ischemia and severe head injury
High morbidity and mortality
Effacement of the cortical sulci and basal cisterns
Loss of gray/white matter interface
White cerebellum sign

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89. Cerebral herniation Types: - Subfalcine
Mechanical displacement of the brain secondary to mass effect
Causes neurologic dysfunction and vascular compromise
Types:
- Subfalcine
- Transtentorial (descending, ascending)
- Tonsillar

91. Cerebral herniation Subfalcine herniation:
- The cingulate gyrus slips under the falx cerebri
- Compression of the ipsilateral ventricle and enlargement of the contralateral ventricle
- ACA ischemia

93. Cerebral herniation - PCA ischemia
Descending transtentorial herniation (uncal):
- The medial temporal lobe displaces through the tentorial notch
- Presents clinically with deteriorating level of consciousness, ipsilateral 3rd nerve palsy and contralateral motor deficit
- Effacement of the ipsilateral suprasellar cistern and enlargement of the ipsilateral CPA cistern
- The midbrain impacts the contralateral tentorium (Kernohan’s phenomenon, Duret hemorrhage)
- PCA ischemia

94. Cerebral herniation