1. Micelle Haydel, MD LSU-New Orleans
Head CT Basics : Trauma
Micelle Haydel, MD
LSU-New Orleans

2. First, a little test…

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12. Head CT Interpretation the basics

13. A Little History...
In the early 1970s, Hounsfield developed a way of computerizing Xrays to select certain densities for viewing.
Plain films: black, white or a few shades of grey
CT: thousands of shades of grey based on the density of the tissue (Hounsfield Units)

14. What We Need to Know Air is very black (less than -300 HU)
Water/CSF is black (near 0 HU)
Bone is very dense/white ( HU)
Blood is white (60-80 HU)
Brain is gray HU

15. Before we look at abnormal, A little normal geography:
Use the Cisterns& Ventricles as landmarks
4th
Supra
Quad
3rd

16. 4th Ventricle

17. Suprasellar Cistern

18. Sella turcica
Suprasellar
Suprasellar Cistern

19. 3rd Ventricle
Quadrigeminal
Cistern

20. Temporal Horn of Lateral Ventricle

21. 3rd Ventricle & Quadrigeminal Cistern

22. Lateral Ventricles
Frontal
Occipital

23. Lateral Ventricles

24. Review:
Temp Horn
Suprasellar
3rd
Quad
4th

25. Normal Head

37. ABNORMAL CTs

38. On each brain slice look for:
Symmetry, symmetry, symmetry
sulci
cisterns and ventricles
grey-white differentiation

39. Identify What Doesn’t Belong Hyperdensities (whiter)
extra-axial hematomas (SDH, EDH)
ICB or contusion
SAH in sulci, cisterns or ventricles
Hypodensities (darker)
pneumocephaly (air is darker than CSF)
infarction

40. Identify What Doesn’t Belong
Localized or diffuse edema
effacement of sulci or cisterns
distortion of gray-white matter interface
enlarged ventricles, temporal horn
Fractures
soft tissue swelling
fluid (blood) in sinuses or mastoid air cells
in children, look for widened sutures
Always look at bone windows

41. Blood: Acute blood is white (60-80 HU) on CT, due to the density of hemoglobin.
As hgb breaks down, the HU decrease (i.e. subacute and isodense hematomas)

42. Dura mater Pia mater Arachnoid Dura tightly adhered
to skull, but loosely to brain.
Dura mater
Arachnoid
Pia mater

43. Epidural Hematoma Lens shaped (dura tightly adhered to skull
Can cross midline
Frequently assoc. with fracture

44. Small Epidural Hematoma

45. Very Small Epidural Hematoma

46. Epidural with fracture

47. Very Small Epidural Hematoma with fracture

48. Epidural with Pneumocephaly

49. Subdural Hematoma
Follows the contour of the brain & doesn’t cross the midline

50. Small SDH tracking down midline

51. Small Subdural Hematoma

52. Very Small Subdural Hematoma

53. Large Subdural Hematoma with shift

54. Isodense Subdural Hematoma

55. Hygroma with shift s/p SDH

56. Acute on Chronic Subdural Hematoma

57. Intraparenchymal Bleed

58. Intraparenchymal Bleed & Skull Fracture

59. Intraparenchymal Bleed & Contusions

60. Contusion

61. Pneumocephaly and contusion

62. Subarachnoid hemorrhage-
Blood in the 4th Ventricle

63. Subarachnoid blood in the suprasellar cistern

64. Subarachnoid blood tracking along the sulci

65. Intra-Ventricular Blood throughout

66. Temporal Horn enlargement
Subdural hematoma

67. Epidural
Enlarged Temporal Horn

68. Diffuse Edema, SAH tracking across tentorium

69. Subfalcean herniation (midline shift) due to SDH

70. Uncal herniation (EDH & subfalcean herniation)

71. Diffuse Edema s/p SAH

72. Soft-tissue swelling
Fracture

73. ….the results

74. 1.
Epidural Hematoma

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Skull Fracture
SAH

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Cerebral Contusion

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SAH

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Subdural Hematoma
Subfalcean Herniation

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Epidural Hematoma

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Diffuse Edema

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Isodense Subdural

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Subdural Hematoma

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