The document discusses several pathologies that can cause proptosis (forward displacement) of the eye including orbital pseudotumor, Graves' ophthalmopathy, optic neuritis, and lymphoproliferative lesions of the orbit. Orbital pseudotumor is a non-granulomatous inflammatory process that can involve any orbital structure. Graves' ophthalmopathy is associated with thyroid dysfunction and causes enlargement of the extraocular muscles. Optic neuritis typically causes enlargement and enhancement of the optic nerve. Lymphoproliferative lesions include benign lymphoid hyperplasia and lymphomas, appearing as enhancing masses or infiltrative lesions.

1. ORBITAL IMAGING VI

3. 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.

4. 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.

5. 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.

6. 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.

7. 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.

8. 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.

9. Orbital pseudotumor:

10. 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.

11. Orbital pseudotumor:

12. Orbital pseudotumor:

13. Orbital pseudotumor:

14. 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.

15. 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.

16. Graves ophthalmopathy:
 CT imaging:
 Iso-dense enlargement
of EOMs.
 Heterogeneous low
density area contents.
 Hypertrophied retro-
bulbar fat.
 Heterogeneous
increased
enhancement of
involved muscles.

17. Graves ophthalmopathy:

18. Graves ophthalmopathy:

19. 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.

20. Graves ophthalmopathy:

21. Graves ophthalmopathy:

22. 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%.

23. Optic Neuritis:
 CT imaging:
 Usually normal.
 May show minimal
optic nerve
enlargement.
 On post contrast
imaging, segmental
enhancing criteria.

24. 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.

25. Optic Neuritis:

26. Optic Neuritis:

27. Optic Neuritis:

28. 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.

29. 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%.

30. 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 %.

31. Lympho-proliferative lesions
of the orbit:
 Moderate diffuse
enhancement.
 Followed by decrease
enhancement on
delayed scan.

33. 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.

34. Lympho-proliferative lesions of
the orbit:

35. Lympho-proliferative lesions of
the orbit:

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