ORBITAL IMAGING

Head and Neck Imaging.Ehab Abo-Ulfotouh Helal.

Lecture Of Radio-Diagnosis.

Orbital Lesions: DifferentiatingVascular and Nonvascular Lesions.

Mass effect on the orbits can lead to clinical presentations such as:

- Proptosis, pulsatile or non.

- Orbital pain

- Visual loss.

- Diplopia.

- Bruit.

vascularlesions, either within the orbits or extraorbital space:

Can alter the normal orbital blood flow pattern.

Lead to vascular engorgement.

Capillary Hemangiomas.

Also known as benign hemangioendothelioma.

Most common orbital vascular tumor in infants.

Entirely extra-conal in location or have a substantial extra-conal component.

superficial or deep, commonly extend across tissue planes, and may extend intra-cranially through the optic canal or superior orbital fissure.

Capillary Hemangiomas.

Extraocular muscles and lacrimal glands occasionally are involved.

Capillary hemangiomas may cause proptosis, globe displacement, and, occasionally, amblyopia.

expand slightly during crying or straining.

isolated findings or may be found in association with other manifestations in various syndromes (PHACE)

Capillary Hemangiomas.

Capillary Hemangiomas.Computed tomography (CT) feature. Non-encapsulated.

Lobulated , irregularly marginated.

Heterogeneous.

Intense homogeneousEnhancement.

Capillary Hemangiomas.

At MR Imaging:Hypointense onT1-weighted images.

Iso- to hyper-intense Lobules with thin septa, combined with intra-lesional and peri-lesional flow voids, characteristic features on T2-weighted images.

Intense enhancement.

Venous Vascular Malformations:Cavernous Malformations.

Also known as cavernous hemangiomas.

Most common vascular lesions in adults.

Manifest with progressive, painless proptosis.

Less common symptoms include pain, lid swelling, diplopia, a palpable lump, and recurrent episodes of obscured vision.

Nature of cavernous malformations: - Venous origin. - low-flow arterio-venous malformations.

Cavernous Malformations.

Solitary, capsulated.

Retrobulbar intra-conal space.

Extend intra-cranially through the superior orbital fissure (5%–10%).

Associations with Maffucci syndrome and blue rubber bleb nevus syndrome.

Cavernous Malformations.

On NECT images.Well circumscribed.

Round or ovoid.

Homogeneously Hyper-attenuating, intra-conal lesions.

Contain micro-calcifications.

May produce expansion of orbital walls.

Cavernous Malformations.

Displace adjacent structures but do not invade them.

On enhanced CT:

Poor enhancement noted in early arterial phase.

Fill centralpart of the lesion on late venous phase.

Cavernous Malformations.

At MR imaging.Isointense to that ofmuscle on T1-weighted images.

Hyperintense to that of muscle on T2-weighted images.

Internal septa are visible within larger lesions.

Progressive accumulation of contrast material onlate phase delayed images.

Venous Lymphatic Malformations.

Term lymphangioma commonly applied to this lesion.

Referred to as no-flow or low-flow vascular malformations.

Evident at birth, but generally manifest in infancy or childhood.

Slowly progressive proptosis, restriction of eye movements, or vertical globe displacement, many manifest abruptly because of hemorrhage.

Venous Lymphatic Malformations.

Diffuse un-encapsulated.

Multi-compartmental, often including both intraconal and extraconal components .

Extend across tissue planes, infiltrate the eyelid and orbit, and cause bone remodeling.

isolated from normal orbital vasculature.

Not affected by postural changes.

Venous Lymphatic Malformations.

MR imaging is the modality of choice.

Signal intensity of the lesions depends on typeof fluid within the cystic components ( T1WIs, Fat supp., T2WIs).

Fluid-fluid levels within multiple cysts.

Variable enhancement.