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The Imaging of the Orbit
This document provides an overview of orbital anatomy and diseases. It describes the major anatomic components of the orbit including the globe, optic nerve, extraconal and intraconal areas. Common pathologies are discussed for each anatomic structure, such as retinoblastoma affecting the globe and optic neuritis involving the optic nerve. Imaging techniques for evaluating the orbit including MRI and CT are also reviewed. Key anatomical structures like the superior orbital fissure and its contents are defined.
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The Imaging of the Orbit
- 1. The Orbit Thorsang R1 Neuroradiologytopic 04.06.2014
- 2. Outline • Orbit overview •Imaging techniques • Orbital anatomy • Diseases of the orbit
- 3. Major anatomic components •Globe • Optic nerve & sheath • Conal-intraconal area • Extraconal area
- 4.
- 5. Imaging techniques MRI • Initialimaging sequence of choice for the orbit and CN II – Intraaxial, sellar, parasellar lesions – More sensitive CT • An adjunctive tool: calcifications – Small meningioma – Retinoblastoma with calcification
- 6.
- 7. Orbital anatomy • Roof •Floor • Medial wall • Lateral wall • Superior orbital fissure • Inferior orbital fissure • Optic canal
- 8. Orbital roof • Frontalbone with frontal sinus • Anteriorly thin • Fossa for lacrimal gland
- 9. Orbital floor • Orbitalplate of maxilla – Thin -> blowout fx* • Orbital process of palatine bone • Orbital surface of zygomatic bone
- 10. Medial orbital wall •Lacrimal groove • Lamina papyracea – Medial blowout fracture* – Spontaneous dehiscence of orbital fat • Into ethmoid sinus • Sphenoid bone
- 11. Lateral orbital wall •Orbital surface of zygomatic bone
- 12. Superior orbital fissure Location •Between roof and lateral wall • Surrounded by sphenoid • Beneath optic canal • Optic strut
- 13. Superior orbital fissure Content •Superior opthalmic vein • CN III, IV, VI • CN V1 >> Conduit between orbital apex-cavernous sinus
- 14. Inferior orbital fissure Location •Between floor and lateral wall • PPF fossa-NSP masticator space
- 15. Inferior orbital fissure Content •CN V2, V3 • N. – from PP gg. • V. – inf. Opthalmic v.- pterygoid plexus >> Deep face inflammatory and neoplastic lesions
- 16. Optic canal • Lesserwing of sphenoid bone • Optic nerve + ophthalmic artery (in dural shealth) • From suprasellar cistern
- 17.
- 18. Intraconal space pathology •Venous vascular malformation • Capillary hemangioma • Venous dilatation – Carotid Cavernous Fistula – Varices • Optic nerve lesions – Optic neuritis • MS • Devic's syndrome • Neuritis due to infection (e.g.herpes zoster) • Autoimmune (e.g.Lupus) • Drugs (e.g.chloramphenicol, ethambutol) – Optic nerve glioma – Optic nerve meningioma – Pseudotumor • Other cranial nerves – Schwannoma of 3rd, 4th and 6th cranial nerve
- 19. Conal space pathology •Thyroid eye disease – usually enlargement of the inferior and medial rectus • Pseudotumor: – idiopathic orbital inflammation • Adjacent inflammation: – sinusitis • Uncommon causes of enlargement of the extra- ocular muscles – glycogen storage disease and lymphoma
- 20. Extraconal area • Fat •Lacrimal gland – Lens-shape – Anterior, superolateral – Lies on levator palpabrae and lateral rectus • Bone
- 21. Extraconal pathology • Abscessdue to sinusitis • Schwannoma of the V1 and V2 • Bone lesions: – Fibrous dysplasia of the sphenoid wing – Metastases – Multiple myeloma • Diseases of the orbital appendages
- 22. Orbital appendages • Lacrimalgland – superolaterally in the orbit – granulomatous, epithelial/glandular, and developmental • lacrimal sac • lacrimal duct – -> inferior terbinate into the nose
- 23. Diseases of theorbit • Globe • Optic nerve & sheath • Conal-intraconal area • Extraconal area
- 24. The ocular space •Anterior chamber: cornea anteriorly and the lens and iris posteriorly – Rupture of the globe – Hemorrhage: also known as anterior hyphema – Cataract – Keratitis: inflammation of the cornea – Periorbital cellulitis • Posterior chamber: posterior to the iris – Glaucoma – Uveitis – Ciliary melanoma The globe
- 25. The globe Vitreous body posteriorto the lens – Rupture – Hemorrhage – CMV infection: especially in HIV – Persistent Hyperplastic Primary Vitreous (PHPV)
- 26. Persistent hyperplastic primary vitreous •Unilateral leukokoria in male infants • Persistent hyaloid canal • Persistence of the primary vascular vitreous • Hyperplasia of the residual embryonic connective tissue • PHPV is the second most common cause of leukocoria • Also develops glaucoma and cataract
- 27. • Findings: – Microphtalmicglobe with enhancing increased density in the vitreous humor. – Unilateral/bilateral tissue density band from back of the lens to the posterior inner globe (Persistent Cloquet’s canal) – Retinal detachment (occurs in 30-55%) Persistent hyperplastic primary vitreous
- 28.
- 29.
- 30. Retina • Retinoblastoma: – acommon tumor in children • Hemangioblastoma: – most common retinal tumor in the adult – von Hippel Lindau disease • Detachment: – most common retinal lesion – diabetic retinopathy
- 31. Retinoblastoma • Common tumorin the first year of life • Child < 3 years of age (98%) • Other presentations: leukokoria, strabismus, decreased visual acuity, family hx, eye pain, proptosis • Believed to arise from neuroectodermal cells
- 32. • 75% unilateral;25% bilateral • All bilateral cases are hereditary (AD) >> deficient tumor suppression gene on chromosome 13 • 90% calcified Retinoblastoma
- 33. Retinoblastoma • The othertumors in this age group are – Neuroblastoma – Wilm's tumor – Leukemia – Teratoma.
- 34. Retinoblastoma • Techniques – CTis prefered to detect calcification – MR serves an adjunctive role • Findings: – CT: an intraocular mass with calcification in a child<3 yr -> should consider retinoblastoma – Extraocular spreading along the optic nerve – Together with pinealoma -> trilateral retinoblastoma
- 35.
- 36. DDx in achild with leukokoria • Toxocara endophthalmitis • Persistent hyperplastic vitreous • Retinopathy of prematurity • Coat’s disease
- 37. Calcifications • In adults –most common at the annulus of Zinn – at the optic nerve head within the eye -> optic disc drusen (asymptomatic, but pseudo-papilledema from PE) • In children – retinoblastoma until proven otherwise
- 38. Coat’s disease • Arare eye disorder: congenital non-hereditary vascular malformation of the retina – multiple telangiectatic vessels -> exudate leakage -> retinal detachment • A 6-to-8-year-old boy with unilateral leukokoria • Symptoms occurs when the retina detaches -> central visual loss • Findings: – Increased density of the vitreous – Normal globe size, lack of calcification
- 39.
- 40. Choroid • Melanoma: – choroidcontains the melanin cells • Metastases: – choroid is the most vascular structure in the eye • Detachment: – usually post-traumatic
- 41. Uveal melanoma • Themost common primary intraocular malignancy in adult • A 50-to-70-year old with unilateral ocular complaint • 85% from choroid, 9% from ciliary body, and 6% from iris • Dx from PE + U/S • CT/MR when opaque ocular media prevents a clear view
- 42. Uveal melanoma – Findings •Soft tissue mass adjacent to outer layer of the globe that bulges inward toward the vitreous • Mushroom cloud appearance • Hyperintense on T1 and hypointense on T2
- 43. Sclera • Infection: – Sinusitis –Viral • Pseudotumor • Detachment
- 44. Scleritis • granulomatous inflammatorydisorder • Erythema and chemosis • Characteristics – optic disk edema – exudative retinal detachment – Choroidal folds and scleral thickening >> elevated mass
- 45. • Findings: – CT: •thickened posterior sclera, may enhanced • Thickening of extraocular muscles can also be seen – Magnetic resonance imaging • nodular elevation into the vitreous • Iso-to-hyperintense to normal sclera on T1 • Hypointense on T2 • moderate to marked inhomogeneous enhancement with Gd • A retinal detachment appears as a crescent-shaped area that is hyperintense on both T1 and T2 Scleritis
- 46.
- 47. • collapsed globe(flat tire appearance) Globe Rupture
- 48. • presence ofintra-ocular air or a foreign body • thick posterior sclera • hazy outline of the globe • enlarged anterior chamber Globe Rupture
- 49. Retinal and choroidaldetachment • Retinal epithelium ends at the ora serrata – > retinal detachment will not go beneath it • Retinal detachment with hemorrhage – adults with DM and HTN – shaken baby syndrome • Choroidal detachment – recent intraocular surgery – trauma
- 50.
- 51.
- 52.
- 53. Coloboma • A congenitalglobe defect, usually at the optic nerve insertion point • Often there is microphtalmia and the eye protrudes inferiorly. • 10% also have other CNS anomalies. • Findings: – a small globe with a cystic outpouching of vitreous at the optic nerve attachment site. – Retroocular cyst
- 55. Coloboma • Coloboma canbe part of the CHARGE syndrome: – Coloboma – Heart anomalies – choanal Atresia – Retardation of growth and development – Genital and Ear anomalies. • Coloboma can also be part of the COACH syndrome: – Cerebellar vermis hypoplasia, – Oligophrenia (MR) – congenital Ataxia – Coloboma – Hepatic fibrosis.
- 56. Diseases of theobit • Globe • Optic nerve & sheath • Conal-intraconal area • Extraconal area
- 57. Optic neuritis • Presentations –Visual loss over hours to days – Pain on movement and tenderness when pressure applied to globe • Sporadic/multiple sclerosis – If found, T2 whole brain should be done • Less common causes – pseudotumor, sarcoidosis, radiation, viral, TB, syphilis neuritis
- 58.
- 59.
- 60.
- 62. Optic nerve/sheath tumor •Optic nerve sheath meningioma • Optic nerve glioma
- 63. Meningioma • The mostcommon optic nerve sheath tumor • ischemic neuropathy due to venous obstruction • progressive visual loss, papilledema, optic atrophy, pale disc • Strong association with NF-2 • Abnormal enhancement of the optic nerve sheath • Calcifications 20-50%
- 64. Abnormal enhancement of theoptic nerve sheath
- 65. Optic nerve glioma •Juvenile pilocytic astrocytomas WHO type 1 • Anywhere along the optic tract from the occipital region to the chiasm and the optic nerve • 50% of optic nerve glioma have NF1. • Only 10% of NF1 have optic nerve glioma. • Less commonly cystic in NF than in non-NF • Age 4-5 years and only 20% of patients have visual symptoms.
- 66. Neurofibromatosis type I Atleast 2 of • Six cafe au lait macules • Two neurofibromas of any type or 1 plexiform neurofibroma • Multiple freckles in the axillary or inguinal region • Bone dysplasia • Optic glioma • Two or more iris hamartomas (Lisch nodules) • A first-degree relative with NF1
- 67. Optic nerve glioma T2T1fs + Gd
- 68. Diseases of theobit • Globe • Optic nerve & sheath • Conal-intraconal area • Extraconal area
- 70. Thyroid opthalmopathy • Compressiveoptic neuropathy – Direct compression by the muscles – Ischemic by compression of the vessels
- 71. Idiopathic inflammatory pseudotumor •Idiopathic inflammation of the orbit • Any part of the orbit: muscles, tendons, fat, optic nerve, nerve sheet, lacrimal gland
- 72.
- 73.
- 74. Diseases of theobit • Globe • Optic nerve & sheath • Conal-intraconal area • Extraconal area
- 75.
- 76. Periorbital abscess • Complications –Venous thrombosis of the superior and inferior ophthalmic vein – Cavernous sinus thrombosis and cavernous- carotid fistula in certain fungal sinusitis (e.g.aspergillosis)
- 77. Orbital and periorbitalcellulitis • A 'red hot eye' and proptosis • Orbital VS periorbital cellulitis -> >> the orbital septum << • Periorbital cellulitis – The orbital septum and the superficial part – OPD—PO ATB • Orbital cellulitis – the structures posterior to the septum are also involved. – IPD--IV ATB
- 78.
- 79. Proptosis with sphenoidwing lesion Four sphenoid wing lesions that can cause proptosis: • Fibrous dysplasia • Paget's disease • Meningioma with hyperostosis of the sphenoid wing
- 80. Orbital appendages • Lacrimalgland • lacrimal sac • lacrimal duct
- 81. Lesions of thelacrimal gland • Inflammation – The most common lesions of the lacrimal gland – i.e. Sjoegren's, TB, fungus, pseudotumor – Do not cause masses Children – congenital obstructions of the valves in the lacrimal duct -> dacryocystoceles adults – strictures from ethmoid sinusitis or stones -> epiphera or increased tearing
- 82.
- 83. • Lacrimal glandmass – Lymphoma – Pleomorphic adenoma – Epithelial tumors (adenoid cystic tumor) Lesions of the lacrimal gland
- 84. Tumors • Epidermoid anddermoid tumors – Developmental – Usually arises anteriorly between the globe and orbital periosteum – Well-circumscribed cystic masses containing debris – Dermoid may contain fat, teeth, and hair
- 85. Vascular malformation • Carotidcavernous sinus fistula • Cavernous hemangioma • Capillary hemangioma • Lymphangioma
- 86. Carotid cavernous sinusfistula Cavernous carotid a. —cavernous sinus
- 87. Capillary hemangioma • 6-12months of age • Involutional at 5-7 years of age • Mostly skin, but also in the extraconal of the eye • PHACE-syndrome: – Posterior fossa malformations, – Hemangiomas – Arterial anomalies – Cardiac malformation – Eye abnormalities such as coloboma, glaucoma • CT—irregular margin
- 88.
- 89. Venous vascular malformations •The most common intraconal mass in an adult • 45-year-old women with slow progressive proptosis, diplopia, visual loss • Most are unilocular • CT – Phleboliths – sharply circumscribed, round, dense mass – Spare apex – Bony erosion
- 90.
- 91. lymphatic malformation • Lymphangioma •Childhood onset (60% before 16 y/o) • May abruptly hemorrhage resulting in fluid-fluid levels • May be extraconal or multicompartmental • Association with intracranial malformations – Turner's – fetal alcohol syndrome • Absence of contrast enhancement in pure lymphatic lesions
- 92.
- 93. orbital varix • Propulsionof the eye during straining • During valsalva -> extreme dilation Valsalva
- 94. Conclusion • Orbital anatomy •Disease approach • Diseases of the orbit
- 95. Approach to diseases •Globe • Optic nerve & sheath • Conal-intraconal area • Extraconal area
- 96.
- 97.
- 98.
- 99. References • Harnsberger, H.Ric., and H. Ric. Harnsberger. Handbook of Head and Neck Imaging. St. Louis: Mosby, 1995. Print. • Grossman, Robert I., and David M. Yousem. Neuroradiology. Philadelphia, PA: Mosby Elsevier, 2010. Print. • "Orbita - Pathology." The Radiology Assistant :. N.p., n.d. Web. 20 May 2014
- 100.