Orbital imaging vi


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Orbital imaging vi

  2. 2. Orbital pseudotumor:  Orbital pseudo-tumor is one of the most common causes of unilateral proptosis.  It is generally a disease of middle age and has an acute onset.  A painful ophthalmoplegia and edema of the eyelid or conjunctiva are present in 50% of the patients.  Regression with steroid therapy is considered a specific sign of the disease.  Pseudoturnor may involve any or all intra- orbital structures.
  3. 3. Orbital pseudotumor:  Non-granulomatous orbital inflammatory process.  The second most common cause of exophthalmos.  Infiltrative or mass like soft tissue seen invading any orbital structure.  irregular margins and extends across multiple compartments.  May mimic neoplasm or aggressive infection.  May extend intra-cranially.
  4. 4. Orbital pseudotumor:  Categorized by areas of involvement: A- Myositic pattern: * Most common pattern. * Involving any muscle and mutiple muscle on 50%. * Involving tendinous insertion with tubular configuration. B- Lacrimal pattern: * 2nd most common type. * Diffuse oblong enlargement, particularly antero- posterior dimension.
  5. 5. Orbital pseudotumor: C- Anterior (eye and retrobulbar fat) pattern: *3rd most common type. * Variable involvement of retro-bulbar fat and nerve. *Uveal-scleral form shows thickened sclera and shaggy enhancement. * Peri-neuritic form shows irregular nerve sheath thickening and enhancement. D- Diffuse (intra-conal- multi compartement) pattern: *Overlap with anterior and other pattern. *Frequently tume-factive and mass like appearance.
  6. 6. Orbital pseudotumor: E- Apical (apex, intra cranial) pattern: * Less common, involves orbital apex with posterior extension through fissure. * Tolosa-Hunt syndrome considered intra-cranial variant with extension through cavernous sinus.
  7. 7. Orbital pseudotumor:  CT imaging:  Focal & infiltrative.  Poorly circuscribed.  Mass or thickening on muscle, lacrimal and orbital structures.  Moderate diffuse enhancement.  Increase attenuation on late enhancing phase.
  8. 8. Orbital pseudotumor:
  9. 9. Orbital pseudotumor:  MR imaging:  Hypointense tonormal muscle on TIWIs.  Iso-intense to slighly hyper-intense on T2WIs and STIR.  Due to high cellular component and fibrosis.  Marked diffuse in- homogenous enhancement.
  10. 10. Orbital pseudotumor:
  11. 11. Orbital pseudotumor:
  12. 12. Orbital pseudotumor:
  13. 13. Graves ophthalmopathy:  Is the most common cause of exophthalmos in adults.  Graves ophthalmopathy usually occurs 5 years after the onset of thyroid disease.  Autoimmune inflammation condition associated with thyroid dys-function.  Classically spindle-shaped enlargement of the extra-ocular muscles is observed, with sparing of the tendinous insertion.  The inferior, medial, superior, and lateral rectus muscles (listed in order of decreasing frequency of involvement) may be involved.
  14. 14. Graves ophthalmopathy:  These findings are usually bilateral (90%)and symmetric (70%).  Isolted muscle involvement on 5%, particularly superior rectus.  Additional imaging findings include increased orbital fat, lacrimal gland enlargement, eyelid edema, stretching of the optic nerve, and tenting of the posterior globe.  Treatment is primarily conservative, with radiation therapy reserved for reduction of tension on the optic nerve.
  15. 15. Graves ophthalmopathy:  CT imaging:  Iso-dense enlargement of EOMs.  Heterogeneous low density area contents.  Hypertrophied retro- bulbar fat.  Heterogeneous increased enhancement of involved muscles.
  16. 16. Graves ophthalmopathy:
  17. 17. Graves ophthalmopathy:
  18. 18. Graves ophthalmopathy:  MR imaging:  Isointense enlargement of EOMs on T1WIs.  Increase EOM signals on acute phase and decrease signal on chronic phase on T2WIs and STIR.  Heterogeneous enhancement of involved muscles.
  19. 19. Graves ophthalmopathy:
  20. 20. Graves ophthalmopathy:
  21. 21. Optic Neuritis:  Two type of acute ON : A- MS associated ON. B- Idiopathic isolated mono-symptomativ ON. *Diffuse only enlargement of optic nerve with central or peripheral enhancing pattern. *Unilateral on 70%. *segments of nerve involvement: a- Anterior intra-orbital.45%. b- Mid intra-orbital 60%. c- Intra-canalicular 35%. d- Pre-chiasmatic and chiasma 7%.
  22. 22. Optic Neuritis:  CT imaging:  Usually normal.  May show minimal optic nerve enlargement.  On post contrast imaging, segmental enhancing criteria.
  23. 23. Optic Neuritis:  MR imaging:  Mildly enlarged optic nerve with ill defined border on T1WIs.  Enlarged optic nerve with egmental bright signal on T2WIs and STIR.  Central or peripheral tram track enhancing pattern on post contrast imaging.
  24. 24. Optic Neuritis:
  25. 25. Optic Neuritis:
  26. 26. Optic Neuritis:
  27. 27. Lympho-proliferative lesions of the orbit:  LPLO spectrum including benign and malignant tumors: A- Lymphoidal hyperplasia 10-40%: * Reactive or hyperplasia. B- Lymphoma (NHL) 60-90%. * Homogenus enhancing mass lesion any where on the orbit. * Lobulated well defined margins. *May be have infiltrative presentation pattern or associated inflammatory changes.
  28. 28. Lympho-proliferative lesions of the orbit:  Locations: A-Anterior extra-conal orbital space, centered on superior temporal quadrant. B- Lacrimal gland. C- Diffuse infiltrative pattern with intra-conal component and peri-neural involvement. D- Intra-cranial extension with predilection for pituitary stalk. * Bilateral presentation in 25%. * Multifocal within orbital region in less than 5%.
  29. 29. Lympho-proliferative lesions of the orbit:  CT imaging:  Iso dense to slightly hyper-dense.  Homogenous on malignant lymphoma.  In-homogenous on hyperplasia.  Rare calcification in less than 5 %.
  30. 30. Lympho-proliferative lesions of the orbit:  Moderate diffuse enhancement.  Followed by decrease enhancement on delayed scan.
  31. 31. Lympho-proliferative lesions of the orbit:  MR imaging:  Homogenous mildly hyper-intense to muscle on T1WIs.  mildly hyper-intense on T2WIs and STIR.  Moderate to marked homogenous enhancement.
  32. 32. Lympho-proliferative lesions of the orbit:
  33. 33. Lympho-proliferative lesions of the orbit:
  34. 34. THANKS FOR YOU