This document provides information about NCCT and CECT of the brain and orbit. It discusses anatomy, indications, protocols, and findings. Key points include: 1. It describes the anatomy of the skull, brain, meninges, ventricles, and orbit. 2. Indications for NCCT include suspected hemorrhage, masses, trauma, etc. CECT is used for evaluating tumors, aneurysms, and strokes. 3. Protocols are provided for brain and orbit NCCT and CECT, including patient preparation, positioning, scan parameters, and radiation doses. 4. Types of hemorrhages are discussed along with their appearances on CT. Common pathologies of the orbit are

1. NCCT AND CECT BRAIN AND ORBIT
Suman Duwal
B.Sc MIT
NAMS, BIR HOSPITAL

2. CONTENTS
• Anatomy
• Indications
• Patient preparation
• Contraindication
• Protocol
• Department protocol
• Radiation dose

3. ANATOMY
CRANIUM
NEUROCRANIUM VISCEROCRANIUM
• Includes cranial bones • Includes facial bones

4. NEUROCRANIUM
• Frontal bone
• Parietal bone
• Occipital bone
• Temporal bone
• Sphenoid bone
• Ethmoid bone

5. F
R
O
N
T
A
L

6. Sagittal suture
Superior view

7. P
A
R
I
E
T
A
L
Coronal suture
Squamous suture
Lamboidal suture

8. O
C
C
I
P
I
T
A
L

9. T
E
M
P
O
R
A
L

10. S
P
H
E
N
O
I
D

11. E
T
H
M
O
I
D

12. FONTANELLES IN NEONATE BRAIN

13. CONTENT OF THE CRANIUM?

14. Fig: embryonic development of human brain

15. Fig : different parts of brain

16. Fig: different lobes of the brain

17. Fig: meninges of the brain

18. Fig: gyrus and sulcus

19. Fig: sagittal section of the brain

20. Fig:sagittal section of the brain

22. Fig: basal ganglia

24. Fig: brain stem

25. Fig: ventricles in the brain

26. Fig: CSF circulation

27. CISTERNS

28. • Fig: blood supply to the brain

29. Fig: venous drainage of the brain

30. Name Drains to
Anterior
Sphenoparietal sinuses Cavernous sinuses
Cavernous sinuses
Superior and inferior petrosal
sinuses
Midline
Superior sagittal sinus
Typically becomes right
transverse sinus or confluence of
sinuses
Inferior sagittal sinus Straight sinus
Straight sinus
Typically becomes left transverse
sinus or confluence of sinuses
Posterior
Occipital sinus Confluence of sinuses
Confluence of sinuses Right and Left transverse sinuses
Lateral
Superior petrosal sinus Transverse sinuses
Transverse sinuses Sigmoid sinus
Inferior petrosal sinus Internal jugular vein
Sigmoid sinuses Internal jugular vein

31. Fig: just above the foramen magnum

32. Fig: at the level of fourth ventricle

34. Fig: at the level of third ventricle

36. Fig: at mid ventricular level

37. Fig: above the ventricular level

38. INDICATION NCCT
• Suspected intra-cranial hemorrhage
• Hydrocephalus
• Evaluation of ICSOL
• Head trauma (i.e RTA, fall injury))
• Alteration of mental status (Evaluating psychiatric disorders)
• Suspected mass or tumor
• Increased intracranial pressure
• Immediate postoperative evaluation following brain surgery

39. PATIENT PREPARATION
• History of the patient should be taken along with the reports of previous investigations
• Radiopaque material should be removed from the FOV
• Proper information and instruction should be given to the patient about the procedure
• Uncooperative patient should be sedated

42. DEPARTMENT PROTOCOL(128 SLICE CT PHILIPS INGENUITY)
Patient positioning Supine with head first arms beside the trunk
Scanogram/topogram lateral
Mode of scanning Helical
Landmark Base of the skull to the vertex
Scan orientation Caudo-cranial
Gantry tilt As required, to make scan plane parallel to the canthomeatal line
FOV Skull including the soft tissue
Slice thickness 5mm
Slice interval 5mm
Recon algorithm Medium smooth for brain and sharp kernel for bone
pitch 1
Gantry rotation time 0.4sec

43. Scan parameters for scanogram
KV 120
MA 30
LENGTH 250mm
Scan parameters for helical scan
KV 120
MA 350-450
SCAN TIME 11-13sec
window level and window width
Soft tissue 360ww/60wl
Bone 2000ww/800wl
Brain parenchyma 80ww/40wl

44. CECT(CONTRAST ENHANCED COMPUTED TOMOGRAPHY)
• Suspected mass or tumor
• Aneurysm evaluation
• Fluid collection such as abscess
• Ischemic process such as stroke
• Cerebro-vascular stroke
Not done in case of acute trauma/hemorrhage

45. CONTRAINDICATION
• Hypersensitivity
• Renal impairment
serum creatinine level- 0.7-1.4 mg/dL
serum urea level- 7 to 20 mg/dL
eGFR should be more than 30 ml/min/1.73m²

46. PATIENT PREPARATION
• NPO 4-5 hours prior to the procedure
• Serum creatinine and urea report should be normal
• Informed consent should be signed from patient or his/her close relative
• In case of diabetic patient metformin should be stopped (24-48) hours prior to
the study and (24-48) hours after the study

47. •13 hours prior to procedure, and 7 hours prior to procedure:
Prednisone 50 mg PO or
Hydrocortisone 50 mg IV
•In addition give, 1 hour prior to procedure:
Prednisone 50 mg PO or
Hydrocortisone 50 mg IV and
Diphenhydramine 50 mg PO or 25 mg IV
HISTORY OF SEVERE REACTION OR ANAPHYLAXIS REACTION

48. PROTOCOL FOR CECT BRAIN
Contrast LOCM,IOCM
Administration route Intravenous(IV)
Volume of contrast 50 to 80ml
Rate of injection 3ml/sec( hand injection)
Delay No delay
Slice thickness 5mm
Slice interval 5mm
Dual phase Arterial phase,venous phase

49. GANTRY ANGULATION AND RADIATION DOSE TO THE LENS
Radiation dose reduction to
the lens from 75% to 90%
has been reported follow the
gantry angulation during CT
brain

50. In recent practice instead of the
gantry angulation, chin is depressed
so as to make the glabellomeatal
line parallel to the scan plane which
reduces the unnecessary irradiation
to the lens.

51. CT FOR SELLAR AND PARASELLAR REGION
Indications
• Hypophyseal pathologies
• Sellar abnormalities
• Cavernous sinus thrombosis
• Caroticocavernous fistula
• Tumors
• Trauma

52. PROTOCOL
Patient positioning Supine with head first arms beside the trunk
Scanogram/topogram AP/lateral
Mode of scanning Helical
Landmark Posterior to anterior from level of clivus to the level of sphenoidale(coronal)
Scan orientation Caudo-cranial
Gantry tilt As required, to make scan plane parallel to floor of the sella
FOV Region of interest
Slice thickness 2-3mm
Slice interval 1-1.5mm
Recon algorithm Medium smooth for sellar and parasellar soft tissues and sharp kernel for bone
Contrast 50ml IV at 3 to 4ml/s
3D Recon MPR/MIP

53. COMMENTS
• For cavernous sinuses , FOV should be increased anteriorly to
include the spheno-parietal sinus and the extra orbital part of
the superior ophthalmic vein and posteriorly to include the
superior and inferior petrosal sinus.(coronal scan)

54. RADIATION DOSE IN CT HEAD
• NCCT HEAD:- approx. 2mSv
• CECT HEAD:- approx. 4 mSv

57. HEMORRHAGE
Extra-axial
hemorrhage
Intra-axial hemorrhage
• Epidural(EDH)
• Subdural(SDH)
• Subarachnoid(SAH)
• Intraventricular(IVH)
• Intracerebral
• Basal ganglia hemorrhage
• Pontine hemorrhage
• Cerebellar hemorrhage
• Lobar hemorrhage

58. HOW THE DIFFERENT TYPES OF HEMORRHAGE ARE SEEN ON CT?

59. EPIDURAL/EXTRADURAL
• Lens shaped
• Commonly results from injury to the
middle meningeal artery.
• Result of countercup injuries
• Between duramater and endosteum
of the skull

61. SUBDURAL
• Crescent shaped
• Caused due to the rupture of
bridging veins
• Result of countercup injuries
• Between dura and arachnoid

62. SUB ARACHNOID
Berry aneurysm
Results of ruptured
aneurysm,AVM and head injury

63. INTRAVENTRICULAR
Common in premature infants but less
common in adults
Results from breakage bleeding from
a hypertensive basal ganglia
hemorrhage, brain contusion

64. INTRA-CEREBRAL
• third most common cause of stroke,
after embolic and atherosclerotic
thrombosis.
• Hypertension
• trauma
• hemorrhagic infarction
• septic embolism

65. INTRA CEREBELLAR
• poorly controlled hypertension
• secondary to an underlying
lesion (e.g. tumor or vascular
malformation)

66. ORBIT

67. HOW THE ORBIT IS FORMED ? AND ITS LANDMARKS

68. Fig: frontal bone

69. Fig: orbital surface of the frontal bone

70. Fig: lesser wing of sphenoid
bone

71. Fig: zygomatic process of frontal
bone

72. Fig: greater wing of the sphenoid
bone

73. Fig: orbital plate of ethmoidal
bone

74. Fig: lacrimal bone

75. Fig: frontal process of maxilla

76. Fig: zygomatic bone

77. Fig: orbital surface of zygomatic
bone

78. Fig: maxilla

79. Fig: orbital surface of maxilla

80. Fig: orbital process of palatine
bone

81. WHAT ARE THE OPENINGS IN THE ORBIT AND ITS CONTENT?

82. Fig: supra orbital
foramen
Contents
• Supra-orbital nerve

83. Fig: infra-orbital foramen
Contents
• Infra orbital nerve
passes

84. Fig: optic canal
Contents:
• optic nerve ( cranial
nerve II)
• the ophthalmic
artery

85. Fig: superior orbital fissure
Occulomotor ,
trochlear , abducens,
ophthalmic
nerve(lacrimal, frontal,
naso cilliary branches)
Opthamlic vein

86. Fig: inferior orbital fissure
Contents
infra-orbital artery
and vein

87. Fig: anterior and posterior ethmoidal
foramina
Anterior:
Anterior ethmoidal vein artery
and nerve
Posterior
Posterior ethmoidal vein artery
and nerve

88. Fig: infra-orbital groove
Contents:
infraorbital vessel and nerve

89. Entrance height 35 mm
Entrance width 45 mm
Medial wall length / depth 45 mm
Volume 30 cc
Distance from the back of the globe to the optic foramen 18 mm
ADULT ORBITAL DIMENSIONS

90. WHAT ARE THE CONTENT OF THE ORBITAL CAVITY?

91. •Lacrimal gland
•Eye
•Optic nerve
•Muscles of orbit

92. LACRIMAL GLAND

93. EYE/GLOBE

94. OPTIC NERVE
• Starts froM 2nd layer (straitum opticum) of retina which is highly
nervous layer

95. PARTS OF OPTIC NERVE
• Intraocular portion
• Intraorbital portion
• Intracanalicular portion
• Intracranial portion

96. MUSCLES OF ORBIT
There are two groups of eye muscles
•Extraocular muscles- that move the eyeball within the orbit
•Intraocular muscles- which are within the eyeball itself and control
how the eyes accommodate
• Sphincter pupillae of iris
• Dialator pupillae of iris
• Cilliary muscle
•Muscles of eyelids
• Levator palpebrae superioris

97. Fig: levator palpebrae superioris

98. Fig: superior rectus muscle

99. Fig: inferior rectus muscle

100. Fig: medial rectus muscle

101. Fig: lateral rectus muscle

102. Fig: superior oblique muscle

103. Fig: inferior oblique muscle

104. Superior
rectus
Origin - superior part of common tendinous
ring (anulus of Zinn)
Insertion - anterior half of eyeball superiorly
Innervation - oculomotor nerve (CN III)
Function - elevation, adduction, internal rotation of
eyeball
Inferior
rectus
Origin - inferior part of common tendinous
ring (anulus of Zinn)
Insertion - anterior half of eyeball inferiorly
Innervation - oculomotor nerve (CN III)
Function - depression, adduction, external rotation
eyeball
Medial
rectus
Origin - medial part of common tendinous
ring (anulus of Zinn)
Insertion - anterior half of eyeball medially
Innervation - oculomotor nerve (CN III)
Function - adduction of eyeball
Lateral
rectus
Origin - lateral part of common tendinous
ring (anulus of Zinn)
Insertion - anterior half of eyeball laterally
Innervation - abducens nerve (CN VI)
Function - abduction of eyeball

105. Superior
oblique
Origin - body of sphenoid bone
Insertion - superolateral aspect of eyeball
(deep to rectus superior, via trochlea orbitae)
Innervation - trochlear nerve (CN IV)
Function - depression, abduction, internal
rotation of eyeball
Inferior
oblique
Origin - orbital surface of maxilla
Insertion - inferolateral aspect of eyeball (deep
to lateral rectus muscle)
Innervation - oculomotor nerve (CN III)
Function - elevation, abduction, external
rotation of eyeball
Levator
palpebrae
superioris
Origin - lesser wing of sphenoid bone
Insertion - anterior surface of tarsus, skin of
upper eyelid
Innervation - oculomotor nerve (CN III)
Function - elevation of upper eyelid

106. ARTERIAL SUPPLY OF ORBIT
It is supplied through the the ophthalmic artery and its branches. The main
branches of ophthalmic artery are
1. Central retinal artery:-it is the first and the smallest branch of ophthalmic
artery which supplies to the inner retinal layers
2. Lacrimal artery:- are the largest branches of ophthalmic artery and supply to
the lacrimal glands eyelids and conjunctiva
3. Posterior ciliary artery:- supplies to the posterior uveal tract , sclera and
cornea
4. Muscular branches:- can be divided into the superior and inferior branches
which function is to supply the extraocular muscle

108. VENOUS DRAINAGE OF ORBIT
• t

109. INDICATION FOR NCCT AND CECT
• Detection, exclusion and f/u of orbital space occupying lesion
• Tumors (retinoblastoma in children)
• Abscesses
• Inflammatory or infiltrative pathology
• Trauma and fracture
• Foreign bodies
• Proptosis
• Pathologies of lacrimal gland
• Cavernous sinus thrombosis
• Carotico- cavernous fistula

112. Patient positioning Supine with head first arms beside the trunk
Scanogram/topogram lateral
Mode of scanning Helical
Starting location
End location
Just above the orbital plates
Floor of the orbit
Scan orientation Caudo-cranial
Gantry tilt nill
FOV Superior orbital margin to inferior orbital margin
Slice thickness 2-3mm
Slice interval 2-3mm
Recon algorithm Medium smooth for soft tissues and sharp kernel for bone
pitch 1
Gantry rotation time 0.4sec
DEPARTMENT PROTOCOL FOR NCCT

113. Scan parameters for scanogram
KV 120
MA 30
Scan parameters for helical scan
KV 120
MA 250
SCAN TIME 8-10sec
window level and window width
Soft tissue 360ww/60wl
Bone 2000ww/800wl

114. RADIATION DOSE
• ORBIT AXIAL – 52 mGy
• ORBIT COR - 47 mGy
In cases where the globes are located outside the FOV, the radiation doses
received by the eye lenses could be reduced by a factor of 16, resulting in
only 3.1-3.4 mGy for a complete axial scanning of the inner ear.
Radiation doses to the eye lenses in computed tomography of the orbit and the petrous bone
Neufang KF, et al. Eur J radiol. 1987.

115. WHY CT?
• Urgency of imaging
• Need of the patient
• Claustrophobic
• Implanted pacemakers, ferromagnetic objects
• Weight limit for table/couch
• Clinical indications

116. REFRENCES
• https://www.ajronline.org/doi/full/10.2214/AJR.09.3462
• CT and MRI of the Whole Body John.R.Hagga sixth edition
• Computed Tomography for Technologists, Lois E. Romans
• Netter’s Concise Radiologic Anatomy, Edwaerd C. Weber
• Protocols for Multislice CT, R. Bruening
• Radiopaedia.com
• www.kenhub.com
• Slideshare.net
• Various internet sources.

117. THANK YOU
Fig: skull of the owl monkey