2. ๏ Retinal and Choroidal Detachments:
๏ Retinal detachment may be either rhegmatogenous or
nonrhegmatogenous.
๏ A rhegmatogenous retinal detachment is a full-thickness
tear of the retina and movement of liquefied vitreous into
sub-retinal space.
๏ Nonrhegmatogenous retinal detachment ,result of traction
on the retina .
3. ๏ characteristic V-shape.
๏ The pex at the optic disc
on cross-sectional
images.
๏ MR imaging can
differentiate
serous, proteinaceous, he
morrhagic content on
sub-retnal space.
4.
5. ๏ Fluid accumulation in the subchoroidal space.
๏ Condition that may occur after ocular surgery, trauma
or an inflammatory choroidal process (uveitis).
๏ spares the region of the optic disc, in the posterior
third of the globe.
6.
7. ๏ Retinoblastoma most common intraocular tumor of
childhood.
๏ Aggressive malignant tumor from the immature
retina.
๏ Manifests before the age of 5 years (90%โ95%).
๏ Accounts for 11% of all cancers in the first year of life.
๏ Both heritable and nonheritable forms of
retinoblastoma.
๏ Bilateral (20%โ34%) or multifocal tumors occur in
patients with heritable retinoblastoma.
8. ๏ Leukocoria: the normal
red reflex of the retina is
replaced by a yellowish
or grayish white
color, occurs in 56%โ
72%.
๏ Strabismus (lack of
binocular vision) 22%โ
24%.
9. ๏ Imaging Findings:
๏ Presence of calcifications differentiating
retinoblastoma from other intraocular lesions.
๏ Exophytic growth component can involve the sub-
retinal space.
๏ Retinal detachment.
๏ Cystic spaces reflecting common pathologic finding of
necrosis.
10. ๏ Endophytic tumor grow from the inner, sensory retina
toward the vitreous.
๏ Exophytic tumor growth from the outer retinal surface
toward the choroid.
๏ Mixed endophytic and exophytic tumor growth.
๏ diffuse, infiltrating growth with plaquelike thickening
of the retina, in only 1%โ2%, with lack calcium
deposits.
๏ Complete spontaneous regression, end state as
shrunken, nonfunctioning globe.
11. ๏ CT is the primary modality for evaluation of
children with leukocoria.
๏ Hyper-attenuating mass in the posterior globe.
๏ Calcifications are apparent at CT in 95% of cases.
๏ Smooth or irregular margins.
๏ Extend into the vitreous or the subretinal
space, causing retinal detachment.
๏ Contrast enhancement is seen in 27.5% of cases.
12. ๏ MR imaging : more sensitive for extension .
๏ retinoblastoma follows the signal intensity of gray
matter.
๏ At T1-weighted imaging, slightly hyper-intense to the
ipsilateral vitreous.
๏ At T2-weighted imaging, commonly dark compared to
the vitreous.
๏ Calcification make the tumor appear heterogeneous.
๏ Tumor has heterogenous enhancing pattern.
19. ๏ Non neoplastic lesions that also cause leukocoria, include :
๏ Persistent Hyperplastic Primary Vitreous (PHPV) .
๏ Coats disease.
๏ Larval granulomatosis.
๏ Retinopathy of prematurity.
๏ Retinal astrocytic hamartoma.
20. ๏ Persistence and hyperplasia of fibrovascular tissue
from embryonic primary vitreous.
๏ Persistent hyaloid artery may be seen within the
Cloquet canal.
๏ Second most common cause of leukocoria, accounting
for 19%โ28%.
21. ๏ Microphthalmos, with absent calcification.
๏ Variably sized cone-shaped retro-lental focus of
increased attenuation.
๏ At the apex, a linear band or septum extending to the
posterior pole.
๏ Increased attenuation of the entire vitreous body.
๏ Layered attenuating hemorrhage may be seen in the
globe on subretinal or sub hyaloid space.
๏ Lens appear abnormally small, lucent, or rounded due
to absorption or swelling.
22. ๏ Superior imaging modality for diagnosis of PHPV.
๏ Microphthalmos.
๏ Small retro-lental masses .
๏ Anterior tenting of the retin.
๏ Post contrast imaging showing enhancement of the
retrolental primary vitreous.
23.
24.
25. ๏ A congenital, nonhereditary, unilateral vascular
malformation of the retina with telangiectasis and
aneurysm formation.
๏ Breakdown in the blood-retina barrier.
๏ Fluid contains cholesterol crystals and lipidladen
macrophages.
๏ Accumulation of lipo-proteinaceous fluid.
๏ Thickened retina.
๏ Massive exudative retinal detachment.
26. ๏ Increased attenuation in globe compared to normal
vitreous.
๏ No calcification.
๏ globe appears normal in size.
๏ Post contrastintravenous, linear enhancement of the
anterior margin of the subretinal exudate, corresponding
to the thickened retina with V-shaped configuration.
๏ subretinal space does not enhance.
27. ๏ subretinal exudate has uniform high signal intensity
on both T1- and T2-weighted imagesdue to its high fat
content.
๏ Hemorrhage or fibrosis may confer a heterogeneous
appearance, especially on T2-weighted images.
๏ subretinal space does not enhance.
๏ Mild to moderate linear enhancement at the border
between the exudate and the remaining vitreous.
28.
29. ๏ Ocular larva migrans, a granulomatous reaction in the
vitreous or uvea in response to infestation by the larval
form of nematode T canis or T cati.
๏ CT may demonstrate high attenuation withor without
a discrete mass.
๏ Absence of calcification.
๏ Size of the globe is normal.
๏ Secondary retinal detachment is frequently visualized.
๏ No enhancement.
30. ๏ At MR imaging, a central vitreous mass is usually
visualized.
๏ Isointense to vitreous on T1-weighted images.
๏ Hyperintense or isointenserelative to vitreous on T2-
weighted images.
๏ Sub-retinal exudate may be seen with variable signal
intensity.
๏ Moderate to marked enhancement.