Ncct and cect brain and orbit

it includes the detail about anatomy and procedure of CT examination of head/brain and orbit
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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

21. Fig: basal ganglia

22. Fig: brain stem

23. Fig: ventricles in the brain

24. Fig: CSF circulation

25. Cisterns

26. Fig: blood supply to the brain

27. Fig: venous drainage of the brain

28. 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

29. Fig: just above the foramen magnum

30. Fig: at the level of fourth ventricle

31. Fig: at the level of third ventricle

32. Fig: at mid ventricular level

33. Fig: above the ventricular level

34. 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

35. 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

36. 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 Iterative dose reconstruction i DOSE level 3

37. 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

38. 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

39. 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/1.73m ²  

40. 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

41. 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

42. 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

43. 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

44. 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.

45. Ct for sellar and parasellar region Indications Hypophyseal pathologies Sellar abnormalities Cavernous sinus thrombosis Caroticocavernous fistula Tumors Trauma

46. 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

47. 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)

48. Radiation dose in CT head NCCT HEAD:- approx. 2mSv CECT HEAD:- approx. 4 mSv

49. 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

50. How the different types of hemorrhage are seen on CT?

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

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

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

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

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

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

57. ORBIT

58. How the orbit is formed ? and its landmarks

59. Fig: frontal bone

60. Fig: orbital surface of the frontal bone

61. Fig: lesser wing of sphenoid bone

62. Fig: zygomatic process of frontal bone

63. Fig: greater wing of the sphenoid bone

64. Fig: orbital plate of ethmoidal bone

65. Fig: lacrimal bone

66. Fig: frontal process of maxilla

67. Fig: zygomatic bone

68. Fig: orbital surface of zygomatic bone

69. Fig: maxilla

70. Fig: orbital surface of maxilla

71. Fig: orbital process of palatine bone

72. What are the openings in the orbit and its content?

73. Fig: supra orbital foramen Contents Supra-orbital nerve

74. Fig: infra-orbital foramen Contents Infra orbital nerve passes

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

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

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

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

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

80. 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

81. What are the Content of the orbital CAVITY?

82. Lacrimal gland Eye Optic nerve Muscles of orbit

83. Lacrimal GLAND

84. Eye/globe

85. Optic nerve Starts froM 2 nd layer ( straitum opticum ) of retina which is highly nervous layer

86. Parts of Optic nerve Intraocular portion Intraorbital portion Intracanalicular portion Intracranial portion

87. 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

88. Fig: levator palpebrae superioris

89. Fig: superior rectus muscle

90. Fig: inferior rectus muscle

91. Fig: medial rectus muscle

92. Fig: lateral rectus muscle

93. Fig: superior oblique muscle

94. Fig: inferior oblique muscle

95. 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 of 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

96. 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

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

98. Venous drainage of orbit t

99. 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

100. 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 Iterative dose reconstruction i DOSE level 3 DEPARTMENT PROTOCOL FOR nCCT

101. 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

102. 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 .

103. Why ct ? Urgency of imaging Need of the patient Claustrophobic Implanted pacemakers, ferromagnetic objects Weight limit for table/couch Clinical indications

104. 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, Edwae \ rd C. Weber Protocols for Multislice CT, R. Bruening Radiopaedia.com www.kenhub.com Slideshare.net Various internet sources.

105. THANK YOU Fig: skull of the owl monkey