This document provides an overview of imaging in neuro-ophthalmology and orbital anatomy. It discusses the anatomy and imaging appearance of the visual pathway, optic nerve, extraocular muscles, vessels and nerves in the orbit. Common pathologies are described including papilledema, optic neuritis, tumors of the optic nerve, sellar region, and orbit. Imaging modalities useful for evaluation including CT, MRI, MR angiography and ultrasound are also mentioned. In summary, it serves as a comprehensive review of normal orbital anatomy and variations as well as pathologies of the visual system that can be evaluated with medical imaging.

1. Imaging in Neuro-Ophthalmology &
Revisiting Orbital Imaging
Dr Himadri Sikhor Das
Matrix
http//:www.radiozen.wordpress.com

2. Optic nerve from posterior globe to the Optic Chiasm .
After the characteristic crossing, fibers of optic nerve
travel as Optic Tracts to the Lateral Geniculate Body.
The optic nerve has 2 sets of fibres:
1. Visual going to lateral geniculate body.
2. afferent fibres of the pupillary reflex going to tectum
of midbrain
Motor system( Extraocular nerves)
THE VISUAL PATHWAY

3. Outer layer:
constitutes sclera & transparent cornea anteriorly
fibrous protective layer
Middle layer (uveal tract)
choroid, ciliary body and iris
vascular and nutritive functions contains blood
vessels, numerous nerves, connective tissue, and
pigmented melanocytes.
vascular supply of the uveal tract is important to the
Neuroradiologists, because of the "blood-ocular
barrier", analogous to the BBB, present at several
points.
Inner layer (retina):
consists of a thin, outer retinal pigment epithelium layer
and an innermost sensory retina
contains neural elements for visual perception
Normal Orbital Anatomy (Globe)
THE GLOBE
:

4. Normal Orbital Anatomy (EOM)
6 skeletal EOM insert on the sclera and control
motion of the globe
4 rectus muscles (superior, inferior, lateral, &
medial) arise from a common tendinous ring, the
annulus of Zinn, and form a muscle cone that
inserts onto the front of the sclera

5. Ophthalmic artery
Chief artery of the orbit
Arises medial to the anterior clinoid process from the supraclinoid
internal carotid artery
Superior and inferior ophthalmic veins drain the orbital structures
Normal Orbital Anatomy (Vessels)

6. Normal Orbital Anatomy (Nerves)
● oculomotor (3rd cranial
nerve) is the major motor supply
for movements, supplying
extraocular muscles except the
superior oblique and lateral rectus
muscles.
● trochlear (4th cranial nerve),
supplies only the superior oblique
● abducens (6th cranial nerve)
supplies only the lateral rectus muscle.

7. optic nerve (2nd cranial nerve)
interconnects retina to brain and extends approximately 3.5 to 5 cm between
posterior globe and optic chiasm
approximately 90% of its fibers are afferent
ophthalmic nerve (first division of the 5th cranial nerve)
sensory nerve that receives input from the globe and its conjunctivae, the
lacrimal gland, the nose and nasal mucosa, the upper lid, frontal sinus, scalp,
and forehead
Normal Orbital Anatomy (Nerve)

8. Disturbances of the visual pathway

9. Imaging modalities
●Plain Radiographs
●USG
●CT:
● :Axial
● :Coronal,
● :Reformats
● :3D-VRT
●MRI:
● : DWI
● : MRS
● : MRV
●Carotid angiography (CT,MRI,DSA)
●Orbital Phlebography

10. THE VISUAL PATHWAY
Optic Nerve
Optic Chiasm
Optic Tracts
Optic Radiation

11. THE VISUAL PATHWAY
Lateral Geniculate Body

12. THE VISUAL PATHWAY
Primary Visual (Calcarine) Cortex

13. Optic Nerve is divided to 4 parts:
A-Intraocular
B-Intra-orbital
C-Intra canalicular
D-Intracranial
THE VISUAL PATHWAY

14. Division of Optic Nerves
● All the retinal nerve fibers merge to the optic
nerve here
● Central retinal vessels enter and leave the eye
here
● Absence of photoreceptors at this site creates a
gap in the visual field known as the blind spot.
● Visible on ophthalmoscopy as the optic disc
1. The Intraocular portion:

15. It is particularly important to document the size of the optic
cup. This is specified as the horizontal and vertical ratios of
cup to disc diameter (cup – disc ratio).
Optic cup:
Cavitation of the optic nerve & brightest part of the
optic disc, no nerve fibers exit from it and there is a
correlation between the size of it and the size of the
optic disc.
The intraorbital portion begins after the nerve passes
through a sieve-like plate of scleral connective tissue,
the lamina cribrosa
Intraorbital portion:

16. After the optic nerve passes through the optic canal, the short intracranial
portion begins and extends as far as the optic chiasm.
Like the brain, the intraorbital and intracranial portions of the optic nerve are surrounded by
sheaths of dura mater, pia mater, and arachnoid. The nerve receives its blood supply through
the vascular pia mater sheath.
4. Intracranial Portion of the Optic Nerve:

17. 3rd
nerve (Oculomotor)
4th
nerve (Trigeminal)
6th
nerve (Abducens)
Extraocular Cranial Nerves

18. Nuclear part
Cisternal part
Cavernous portion
Superior orbital fissure (SOF)
Possible sites of involvement

19. Common lesions:
Infarction
Haemorrhage
Demyelination
Tumours
Infection

20. Nucleus :Nuclear involvement
Nuclear Lesions
●Infarction
●Haemorrhage
●Tumours
●Demyelination

21. Nuclear involvement: Demyelination

22. Demyelination 3rd nerve nucleus

23. Aneurysm
Trauma
Vasculitis
Adjacent masses
Meningeal Infections
Lesions of Cisternal
Part

24. (PCoA) aneurysm in pt with left pupil-involving third nerve palsy
MIP image from Circle of Willis
MR angiography
CT Angio with 3D-VRT images of same patient
optimally demonstrates aneurysm sac (dot) &
aneurysm neck (arrow)

25. Acute right occipital lobe infarction
( patient with complete left homonymous hemianopsia) .
DWI- right occipital lobe restricted diffusion ADC map : decreased signal (arrow) confirming acute
ischemic stroke.

26. T2 FLAIR image - hyper intense signal
in both occipital lobes (arrow).
Hypertensive patient (PRES)
Corresponding DWI : iso & hypointense signal (arrow)
consistent with vasogenic edema.

27. SOF

28. Cavernous part
Cavernous Sinus Cavernous parts ( 3rd, 4th & 6th nerve )

29. Cavernous Sinus thrombosis

30. Parasellar Aneurysm compressing 3rd
,4th
& 6th
Nerve
MRA
MIP

31. Lesions common to Cavernous Sinus & Superior orbital fissure
● Idiopathic Orbital Pseudotumour
(Tolosa Hunt Syndrome)
● Lymphoma
(Lymphoma Pseudotumor complex)
● Extension from adjacent SOL’s
● Primary nerve sheath tumor
● CCF

32. Hypertrophic Pachymeningitis

33. Hypertrophic Pachymeningitis

35. Nasopharyngeal carcinoma

36. Diseases of Optic Disc
- Optic Nerve Drusen
- Papilledema
- Papillitis

37. Papilloedema vs optic disc swelling
Papilloedema ●Pseudo papilloedema
●Drusen of the optic disc
●Raised intra orbital pressure.
●Optic nerve tumors

38. Pathophysiology
The disc swelling in papilledema is the result of axoplasmic flow stasis with intra-
axonal edema in the area of the optic disc. The subarachnoid space of the brain is
continuous with the optic nerve sheath.
Hence, as the cerebrospinal fluid (CSF) pressure increases, the pressure is
transmitted to the optic nerve, and the optic nerve sheath acts as a tourniquet to
impede axoplasmic transport. This leads to a buildup of material at the level of the
lamina cribrosa, resulting in the characteristic swelling of the nerve head.
Papilledema may be absent in cases of prior optic atrophy. In these cases, the
absence of papilledema is most likely secondary to a decrease in the number of
physiologically active nerve fibers.

39. normal optic nerve head :
distinct margins,
central pinkish disk.
Papilloedema :showing blurred disc
margins and dilated tortuous vessels

40. Causes:
Any tumors or space-occupying lesions
of the CNS( hematoma abscess,…..)
Decreased CSF resorption (e.g., venous
sinus thrombosis, meningitis,
subarachnoid hemorrhage)
Craniosynostosis (rare) Idiopathic intracranial hypertension
(aka pseudo tumor cerebri)
Cerebral edema/encephalitis Medications, for example, tetracycline,
minocycline, lithium, nalidixic acid, and
corticosteroids (both use and withdrawal)
Obstruction of the ventricular system Increased CSF production (tumors)
Intracranial tumors occupies 60% of the causes

41. - Optic Neuritis
- Optic Nerve Sheath Tumor
Optic Neuritis
Causes
- MS
- Viral Infection
- SLE
- ADEM
- Neurosarcoidosis
- Radiation
Retrobulbar Optic Nerve Lesions

42. Optic Neuritis
MS

43. Optic Neuritis
MS

44. Optic Neuritis
MS

45. Value of fat suppression & fluid attenuation inversion recovery (FLAIR)

46. Post traumatic optic neuritis

47. - Meningioma
- Glioma
Optic Nerve / Sheath Tumour

48. Meningioma

49. Glioma

50. Glioma

51. Sellar / Supra & Parasellar sellar Anatomy

52. ● Craniopharyngioma
● Pituitary adenoma
● Meningioma
● Aneurysm
● Hydrocephalus
Sellar / Suprasellar Masses

53. Hydrocephalus
Cisternal herniation

54. Craniopharyngio
ma

55. Pitutiary Macro-adenoma

56. Pitutiary Macro-adenoma

57. Pituitary apoplexy

58. Haemorrhagic Pitutiary Macro-adenoma

59. Visual Cortex, Optic radiation &
Lateral Geniculate Body
- Infarction
- Haemorrhage
- Demyelination
- Tumours
- Infection

60. Acute ICH
Axial gradient recall echo image showing
marked hypointensity around the acute ICH

61. Anterior compartment:
consists of eye lids, lacrimal
apparatus and anterior soft tissues
Posterior compartment
(Retrobulbar space):
divided into intraconal and
extraconal spaces
The cone:
consists of extraocular muscles and
an envelope of fascia
optic nerve is located within the intraconal
space
Normal Orbital Anatomy (Compartments)

63. Thyroid eye disease

64. Idiopathic orbital inflammation ( Pseudo tumor )

65. Classification of tumours of orbit
Intraocular
In paediatric age group
Retinoblastoma
D/D : PHPV
Coat disease
In Adults
Malignant melanoma
Choroidal haemangioma
Metastasis

66. Orbital tumours
In paediatric age group
●Haemangioma
●Rhabdomyosarcoma
●Metastasis from Neuroblastoma
In Adults
●Haemangioma
●Lacrimal gland tumour
●Optic nerve glioma
●Meningioma
●Lymphoma
●Orbital Metastasis from lung, breast,
prostate

67. Retinoblastoma
● Most common tumour
(commonly 1-3 yrs of age)
● Leukokoria in 60% (white pupil)
● Causes leukocoria in other causes include
PHPV, congenital cataract, trauma, retrolental
fibroplasia etc)
● Approx 30% bilateral
● ( 90% )associated with inherited forms)

68. ●commonly : posterolateral globe wall
●solid, retrolental hyperdense mass (endophytic type)
●most common cause of orbital calcifications (90%; fav prog sign)
●retinal detachment invariably present
●usually enhances with contrast (poor prog sign)
●extraocular extension in 25%: optic nerve enlargement, intracranial extension, abnormal
soft tissue in orbit
Retinoblastoma

69. Retinoblastoma

70. D/D of pineal region masses includes germinoma,
teratoma, and pineocytoma/blastoma
Trilateral Retinoblastoma
30% multifocal in one eye; also may occur “trilaterally”

71. PHPV
●Results due to failure of regression of embryonic hyaloid vascular system.
●Persistence of primary vitreous
●usually unilateral.
Imaging:
Triangular retrolental band of soft tissue extending along Cloquet’s canal from posterior
surface of lens to posterior pole of the globe.
Layering of fluid in sub-retinal space
NO CALCIFICATION
clinical: blindness, leukocoria, microphthalmia (small hypoplastic globe)

72. Coats’ disease
●Primary retina vasular telangiectasis with accumulation of lipoproteinaceous exudates in
retina and subretinal space
●Almost always unilateral
●Boys older than those who have retinoblastoma
●In advanced cases total R.D. may be seen
●Absence of calcification.

73. ●cellular accretions of hyaline-like material in the optic disk , often
familial
●bilateral in 75% , frequently calcify
●many are asymptomatic, arcuate visual field defects may be present
●CT scan shows discrete rounded high densities confined to the optic
disk surface
Optic Nerve Drusen

74. ●deficient closure of embryonic choroidal fissure
●ocular contents herniate posteriorly to retrobulbar space at site of ON attachment
●may be associated with encephalocele and/or agenesis of the corpus callosum
●bilateral in 60%
Coloboma

75. ● MC - adult ocular malignancy
● 6Th
-7th
decades of life
● almost always uniocular and single
● aggressive malignant tumor of uveal tract; most arise from preexisting choroidal nevi
● invades along choroid, into vitreous & through sclera into ON and RB Space
Imaging : CDFI - Mass very vascular
: CT – high density; do not calcify; enhances
: MRI – compared to the vitreous, high signal on T1 and low on T2WI
(secondary to paramagnetic properties of melanin)
●thickening/irregularity of choroid/urea or exophytic/biconcave mass
●sub retinal effusion and retinal detachment very common
●Primary D/D: choroidal metastasis (esp. breast and lung Ca) : moderate signal on T1 and high
signal on T2
Melanoma:

76. Melanoma:

77. Intraocular Metastasis
●Sub retinal masses located in posterior part of fundus.
●flattened or placoid masses and may be multiple.
●Common primary tumors : Lungs, breast, prostate etc.

78. Intraocular Metastasis

79. Orbital Tumours:
Capillary Haemangioma:
●MC vascular tumor of orbit in children
●10% of all pediatric orbital tumors
●first year of life , spontaneously involutes >1 year
●no fibrous capsule (unlike cavernous haemangioma)
●can infiltrate both intraconal/extraconal spaces
●90% associated with cutaneous angiomas
Cavernous Haemangioma:
●Commonest intraorbital tumour in adults
●Commonly intraconal may be extraconal .
●Well encapsulated round, oval or lobulated
●Histologically – large dilated vascular channels (sinusoid like spaces) lined by endothelial cells.
●These contain relatively stagnant blood.
Haemangioma

80. Haemangiom
a
● vascular nature not apparent on MR because they are not high
flow lesions
● most found in intraconal space, lateral to optic nerve

81. Osseous
Haemangioma

82. Cavernous Hemangioma
A.chemical-shift artefact on T2
sequence (indicating the presence
of fat)
B-D. characteristic pattern of
progressive enhancement from
periphery to center with gad

83. Lymphangioma
●Most lymphangiomas present during childhood.
●Benign tumours containing lymphatic channels ( lymph fluid alone / lymph / blood products)
separated by septae.
Imaging: Undulating or irregular margins consisting of septae which separate it into lobules
and cysts of varying size and echo/density/intensity.
The ability to characterise the various stages of evaluation of the haemorrhage makes MR on
ideal diagnostic modality for studying these lesions.

84. Lacrimal gland tumours
● Benign mixed tumours (Pleomorphic adenoma)-MC benign tumour
● Most often involves the orbital part of the lacrimal gland.
● Well defined mass with posterior rounded configuration.
● Fossa formation in superolateral part of bony orbit.
● Presence of calcification, necrosis and bone destruction, all suggestive of malignancy.

85. Lacrimal gland tumours

86. Orbital Dermoids and Epidermoids
MC benign paediatric orbital tumour
congenital developmental tumours arising from
embryonic epidermis that gets trapped in developing
sutures of the orbital bones.
Most frequently located in superolateral quadrant.
Dermoid tumours contain hair and sebaceous glands
containing keratinaceous debris and fatty substances.
Bone changes by expansion and pressure erosion
leading to thinning and scalloping of adjacent bone.
Imaging oval, lobulated, dumb bell, shaped with cystic or
solid components. Orbital bone changes may be seen.
A specific diagnosis can be made if fat fluid level is
demonstrated

87. Orbital Dermoids and Epidermoids

88. OPTIC NERVE GLIOMA
●Common childhood tumour with a female preponderance.
●High association with neurofibromatosis (over 50%).
Plain radiography
●Enlargement of optic foramen may be seen.
●Tubular, fusiform or saccular enlargement of the optic nerve.
●Tortuous course of the nerve goes in favour of optic nerve glioma.
●Contrast enhancement less intense.
●Calcification rarely.
●MRI better evaluates intra canalicular and intracranial parts.

89. Optic Nerve Glioma

90. Optic Nerve Glioma

91. Bilateral Optic Nerve Gliomas

92. Neurofibromatosis

93. Neurofibromatosis with Meningiomas

94. MENINGIOMA OF THE ORBIT
More common in women
occurs most frequently in middle age
Meningiomas of the orbit are of 3 types :
I Sphenoid wing meningioma with extension to the orbit
II Optic nerve sheath meningioma
III Meningioma arising de novo from arachnoid cells in the orbit.

95. Type I : Sphenoid Wing Meningioma
● Results in hyperostosis and expansion of the bone
●
● The osseous tumour as well as soft tissue component
may extend into the orbit, anterior or middle cranial
fossa or extracranially to temporal fossa.
Sphenoid Wing Meningioma

96. Sphenoid Wing Meningioma

97. Sphenoid Wing Meningioma

98. OPTIC NERVE SHEATH MENINGIOMA
Type II : Optic Nerve Sheath Meningioma
● Arises from archnoid cells of the dural sheath covering the optic
nerve.
● Diffuse enlargement of the optic nerve sheath complex results
in a tubular, fusiform or saccular appearance
● Rather straight course.Sheath shows marked enhancement
following IV contrast.
● Calcification is a common feature and may appear diffuse,
coarse, punctate, or tubular shaped along the O.N. sheath.

99. Optic Nerve Sheath Meningioma

100. MENINGIOMA ARISING DE NOVO
Type III :
● Meningioma arising from rests of archnoid cells
inside the orbit.
● Very rare, variety.
● No characteristic features.
● Seen as an orbital mass located in any part of
the orbit.

101. RHABDOMYOSARCOMA
Most common primary orbital malignancy of childhood.
●Mean age of onset 6 yrs.
●Rapidly progressive proptosis
●Tumour arises from extraocular muscles
●Superonasal quadrant most common
●Mass may be associated with bone destruction.

102. Rhabdomyosarcoma

103. LYMPHOMA
More often seen in anterior part of orbit or retrobulbar area
Generally lesions mould themselves to pre-existing structures such as
globe, optic nerve and bony orbit without eroding the bone

104. Lymphoma

105. Leukemia
Squa. Cell Ca. Lower Eyelid

106. ORBITAL METASTASES
Relatively rare
In children
●Neuroblastoma
●Ewing’s sarcoma
●Leukemia
In adults
●Breast
●Lung
●Prostate etc.

107. ORBITAL METASTASES
IMAGING
Infiltrative, poorly defined or well
defined masses.

108. Neuroblastoma Metastases

109. Mets. from Ca Lung

110. CONCLUSIONS
Ocular Tumours
●US has an edge over CT
●CT has a definite complimentary role.
Orbital Tumours
●CT has an edge over US
●CT & MR comparable in general
●CT being cheaper and easily available has wider acceptance.