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The Imaging of the Orbit

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The imaging of the orbit

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The Imaging of the Orbit

  1. 1. The Orbit Thorsang R1 Neuroradiology topic 04.06.2014
  2. 2. Outline • Orbit overview • Imaging techniques • Orbital anatomy • Diseases of the orbit
  3. 3. Major anatomic components • Globe • Optic nerve & sheath • Conal-intraconal area • Extraconal area
  4. 4. Differential diagnoses
  5. 5. Imaging techniques MRI • Initial imaging 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. 6. Imaging techniques
  7. 7. Orbital anatomy • Roof • Floor • Medial wall • Lateral wall • Superior orbital fissure • Inferior orbital fissure • Optic canal
  8. 8. Orbital roof • Frontal bone with frontal sinus • Anteriorly thin • Fossa for lacrimal gland
  9. 9. Orbital floor • Orbital plate of maxilla – Thin -> blowout fx* • Orbital process of palatine bone • Orbital surface of zygomatic bone
  10. 10. Medial orbital wall • Lacrimal groove • Lamina papyracea – Medial blowout fracture* – Spontaneous dehiscence of orbital fat • Into ethmoid sinus • Sphenoid bone
  11. 11. Lateral orbital wall • Orbital surface of zygomatic bone
  12. 12. Superior orbital fissure Location • Between roof and lateral wall • Surrounded by sphenoid • Beneath optic canal • Optic strut
  13. 13. Superior orbital fissure Content • Superior opthalmic vein • CN III, IV, VI • CN V1 >> Conduit between orbital apex-cavernous sinus
  14. 14. Inferior orbital fissure Location • Between floor and lateral wall • PPF fossa-NSP masticator space
  15. 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. 16. Optic canal • Lesser wing of sphenoid bone • Optic nerve + ophthalmic artery (in dural shealth) • From suprasellar cistern
  17. 17. Conal-intraconal area
  18. 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. 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. 20. Extraconal area • Fat • Lacrimal gland – Lens-shape – Anterior, superolateral – Lies on levator palpabrae and lateral rectus • Bone
  21. 21. Extraconal pathology • Abscess due 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. 22. Orbital appendages • Lacrimal gland – superolaterally in the orbit – granulomatous, epithelial/glandular, and developmental • lacrimal sac • lacrimal duct – -> inferior terbinate into the nose
  23. 23. Diseases of the orbit • Globe • Optic nerve & sheath • Conal-intraconal area • Extraconal area
  24. 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. 25. The globe Vitreous body posterior to the lens – Rupture – Hemorrhage – CMV infection: especially in HIV – Persistent Hyperplastic Primary Vitreous (PHPV)
  26. 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. 27. • Findings: – Microphtalmic globe 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. 28. Persistent hyperplastic primary vitreous
  29. 29. The globe
  30. 30. Retina • Retinoblastoma: – a common tumor in children • Hemangioblastoma: – most common retinal tumor in the adult – von Hippel Lindau disease • Detachment: – most common retinal lesion – diabetic retinopathy
  31. 31. Retinoblastoma • Common tumor in 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. 32. • 75% unilateral; 25% bilateral • All bilateral cases are hereditary (AD) >> deficient tumor suppression gene on chromosome 13 • 90% calcified Retinoblastoma
  33. 33. Retinoblastoma • The other tumors in this age group are – Neuroblastoma – Wilm's tumor – Leukemia – Teratoma.
  34. 34. Retinoblastoma • Techniques – CT is 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. 35. Retinoblastoma
  36. 36. DDx in a child with leukokoria • Toxocara endophthalmitis • Persistent hyperplastic vitreous • Retinopathy of prematurity • Coat’s disease
  37. 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. 38. Coat’s disease • A rare 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. 39. Coat’s disease
  40. 40. Choroid • Melanoma: – choroid contains the melanin cells • Metastases: – choroid is the most vascular structure in the eye • Detachment: – usually post-traumatic
  41. 41. Uveal melanoma • The most 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. 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. 43. Sclera • Infection: – Sinusitis – Viral • Pseudotumor • Detachment
  44. 44. Scleritis • granulomatous inflammatory disorder • Erythema and chemosis • Characteristics – optic disk edema – exudative retinal detachment – Choroidal folds and scleral thickening >> elevated mass
  45. 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. 46. T1 fs + C
  47. 47. • collapsed globe (flat tire appearance) Globe Rupture
  48. 48. • presence of intra-ocular air or a foreign body • thick posterior sclera • hazy outline of the globe • enlarged anterior chamber Globe Rupture
  49. 49. Retinal and choroidal detachment • 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. 50. Detachment Retinal Choroidal
  51. 51. Retinal
  52. 52. Choroidal
  53. 53. Coloboma • A congenital globe 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
  54. 54. Coloboma • Coloboma can be 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.
  55. 55. Diseases of the obit • Globe • Optic nerve & sheath • Conal-intraconal area • Extraconal area
  56. 56. 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
  57. 57. Optic neuritis
  58. 58. Multiple sclerosis
  59. 59. Devic's syndrome • Neuromyelitis optica
  60. 60. Optic nerve/sheath tumor • Optic nerve sheath meningioma • Optic nerve glioma
  61. 61. Meningioma • The most common 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%
  62. 62. Abnormal enhancement of the optic nerve sheath
  63. 63. 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.
  64. 64. Neurofibromatosis type I At least 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
  65. 65. Optic nerve glioma T2 T1fs + Gd
  66. 66. Diseases of the obit • Globe • Optic nerve & sheath • Conal-intraconal area • Extraconal area
  67. 67. Thyroid opthalmopathy • Compressive optic neuropathy – Direct compression by the muscles – Ischemic by compression of the vessels
  68. 68. Idiopathic inflammatory pseudotumor • Idiopathic inflammation of the orbit • Any part of the orbit: muscles, tendons, fat, optic nerve, nerve sheet, lacrimal gland
  69. 69. Pseudotumor
  70. 70. Thyroid eye Pseudotumor
  71. 71. Diseases of the obit • Globe • Optic nerve & sheath • Conal-intraconal area • Extraconal area
  72. 72. Periorbital abscess
  73. 73. 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)
  74. 74. Orbital and periorbital cellulitis • 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
  75. 75. Orbital cellulitis
  76. 76. Proptosis with sphenoid wing lesion Four sphenoid wing lesions that can cause proptosis: • Fibrous dysplasia • Paget's disease • Meningioma with hyperostosis of the sphenoid wing
  77. 77. Orbital appendages • Lacrimal gland • lacrimal sac • lacrimal duct
  78. 78. Lesions of the lacrimal 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
  79. 79. Dacryocystocele
  80. 80. • Lacrimal gland mass – Lymphoma – Pleomorphic adenoma – Epithelial tumors (adenoid cystic tumor) Lesions of the lacrimal gland
  81. 81. Tumors • Epidermoid and dermoid tumors – Developmental – Usually arises anteriorly between the globe and orbital periosteum – Well-circumscribed cystic masses containing debris – Dermoid may contain fat, teeth, and hair
  82. 82. Vascular malformation • Carotid cavernous sinus fistula • Cavernous hemangioma • Capillary hemangioma • Lymphangioma
  83. 83. Carotid cavernous sinus fistula Cavernous carotid a. —cavernous sinus
  84. 84. Capillary hemangioma • 6-12 months 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
  85. 85. Capillary hemangioma
  86. 86. 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
  87. 87. Venous vascular malformation
  88. 88. 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
  89. 89. lymphatic malformation
  90. 90. orbital varix • Propulsion of the eye during straining • During valsalva -> extreme dilation Valsalva
  91. 91. Conclusion • Orbital anatomy • Disease approach • Diseases of the orbit
  92. 92. Approach to diseases • Globe • Optic nerve & sheath • Conal-intraconal area • Extraconal area
  93. 93. The globe
  94. 94. Disease approach
  95. 95. Q & A
  96. 96. 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
  97. 97. Thank You

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