Vascular Lesions Of The Orbit

Vascular Lesions Vascular Lesions of the Orbitof the OrbitMore than Meets the EyeMore than Meets the Eye

Smoker et alSmoker et al : From the Departments of Radiology (W.R.K.S., N.K.Y.) and Ophthalmology (J.A.N.), University of Iowa Hospitals and ClinicsFrom the Departments of Radiology (W.R.K.S., N.K.Y.) and Ophthalmology (J.A.N.), University of Iowa Hospitals and Clinics

2008; 28:185–204

Present by Ekkasit S. MD

IntroductionIntroduction

• Vascular lesions of the orbit are uncommon.

• Several possible classification schemes exist: Mulliken and Glowacki, lesions are classified on the

basis of their natural history, including their growth pattern and histologic composition.

Orbital Society, is based on hemodynamic flow

IntroductionIntroduction

Mulliken and GlowackiMulliken and GlowackiDescribed the clinical and imaging features of these lesions in the following groups:

Capillary hemangiomas Venous vascular malformations (cavernous malformations and orbital varices) Venous lymphatic malformations (capillary, cavernous, and cystic lymphatic malformations), Arterial and arteriovenous lesions (arteriovenous malformations, arteriovenous fistulas, and ophthalmic artery aneurysms) Neoplasms (hemangioblastomas, hemangiopericytomas, choroidal hemangiomas, choroidal melanomas, and vascular metastases) Miscellaneous (Coats disease)

The term mixed lesions has been used todescribe those that have characteristics of two or

more different lesions.

Capillary HemangiomasCapillary Hemangiomas

Capillary HemangiomasCapillary Hemangiomas(Benign Hemangioendothelioma)(Benign Hemangioendothelioma)

• The most common orbital vascular tumor in infants ( 5.6% )

• More common in females (female-to-male ratio, 3:2)

• Lesions usually appear at or shortly after birth, rapidly increase in size for 6–12 months, and then gradually involute over the next 5–7 years.


• Superficial lesions appear red, whereas subcutaneous lesions appear blue.

• Proptosis, globe displacement, amblyopia.

• They may expand slightly during crying or straining.


• Most capillary hemangiomas are entirely extraconal in location or have a substantial extraconal component.

• May extend intracranially through the optic canal or superior orbital fissure.

• The extraocular muscles and lacrimal glands occasionally are involved.

• Histologic analysis demonstrates capillary-sized vascular spaces surrounded by proliferating benign endothelial cells.

Copyright ©Radiological Society of North America, 2008

Smoker, W. R. K. et al. Radiographics 2008;28:185-204

Hemangioma


• Complications are rare but may include profuse hemorrhage, thrombosis, optic nerve compression, bone remodeling, and calcification.

• May be found in association with the rare neurocutaneous syndrome known as PHACEPHACE• PPosterior fossa brain malformations

• Large facial HHemangiomas

• AArterial anomalies

• CCardiac anomalies and aortic Coarctation

• EEye abnormalities

( colobomas, optic nerve hypoplasia, increased retinal vascularity, and glaucoma)


Treatment options include observation and topical, oral, or intralesional corticosteroid therapy. Interferon therapy, laser therapy, and surgery typically are reserved for patients with potentially life-threatening complications.


CTCT • The preferred modality for the initial imaging evaluation because it can be performed without sedation.

• Lobulated, irregularly marginated, and heterogeneous.

• Intense homogeneous enhancement after the administration of contrast material.

USUS• Compressible and appear hyperechoic.

Location : entirely extraconal or substantial extraconal component.


CECT

Capillary hemangioma in a 4-month-old boy with proptosis of the left eye, inferior displacement of the globe, and a bluish discoloration under the skin


MRIMRI• Hypointense on T1WI, and iso- to hyperintense on T2WI.

• They enhance intensely after the administration of contrast material .

• Lobules with thin septa, combined with intralesional and perilesional flow voids, are characteristic features.


Axial T1-weighted MR image

Typical capillary hemangioma in a 41/2-month-old girl with proptosis of the right eye and cutaneous hemangioma

Axial T2-weighted fat-suppressed image



Axial contrast-enhanced T1-weighted fat-suppressed image


Venous Vascular Venous Vascular MalformationsMalformations

Cavernous Malformations Cavernous Malformations / / Orbital VaricesOrbital Varices

Cavernous MalformationsCavernous Malformations(cavernous hemangiomas)(cavernous hemangiomas)

• The most common vascular lesions in adults.

• However, their incidence is low overall, with two or fewer cases diagnosed per year at major referral institutions.

• Most often in women (60%–70%) between the ages of mean age, 43–48 years.

• An observed association between cavernous malformations and abrupt proptosis during puberty or pregnancy is suggestive of a contribution by hormone- or cytokine-mediated angiogenic factors to lesion growth.


• Common symptom : progressive, painless proptosis (discovered incidentally at imaging evaluations).

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

• Usually are solitary and most often occur in the lateral aspect of the retrobulbar intraconal space. Rarely involve intramuscular, orbital apex ( monocular vision loss due to the compression of blood vessels that supply the optic nerve.

• Occasionally extend intracranially through the superior orbital fissure, remodeling and intralesional calcification


At histologic analysis, large dilated vascular channels lined by flattened or attenuated endothelial cells with an

intervening fibrous interstitium are visible


ManagementManagement• Usually conservatively.

• Surgical excision is reserved for those that cause severe proptosis or optic nerve compression.

• Because of the inaccessibility of the small feeding arteries and the multiple collateral pathways available for recanalization, embolization therapy is not often performed.


USUS• Well-defined borders due to the pseudocapsule, moderate acoustic attenuation from intravascular blood, and a honeycomb-like structure.

• Color Doppler US is useful for detecting and quantifying blood flow and for mapping the vasculature for surgical planning.


CTCT• Typically : well circumscribed, round or ovoid, homogeneously, hyperattenuating, intraconal lesions.

• Occasionally : microcalcifications(phleboliths) ,may produce expansion of the orbital walls, may displace adjacent structures but do not invadedo not invade them.

• At multiphase dynamic contrast material– enhanced CT, poor enhancement is noted in the early arterial phase because of the low-flow arterial supply; contrast material contrast material does not fill the central part of the lesion until the late venous does not fill the central part of the lesion until the late venous phasephase..


CECT

Cavernous malformation in a 39-year-old woman with painless progressive proptosis


MRIMRI• Isointense to that of muscle on T1WI

• Hyperintense to that of muscle on T2WI.

• Internal septa are visible within larger lesions.

• Progressive accumulation of contrast material on late phase dynamic images and delayed images.



Large cavernous malformation in a 43-year-old woman with painless proptosis of the right eye


Axial contrast enhanced T1-weighted fat-suppressed, image, obtained immediately after the intravenous administration of a gadolinium-based contrast material



Axial contrastenhanced T1-weighted fat-suppressed MR image, obtained 1 hour later



Large cavernous malformation cavernous malformation in a 43-year-old woman with painless proptosis of the right

eye

Orbital VaricesOrbital Varices

• Most common cause of spontaneous orbital hemorrhage.

• Typically manifest in the 2nd or 3rd decade of life, males and females equally.

• Often occur in association with contiguous or noncontiguous intracranial venous anomalies.

• Most varices have a large communication with the venous system and distend during maneuvers that increase venous pressure. (Stress proptosis )

• However, some have only a small communication with the venous system and do not distend but, instead, manifest with thrombosis and hemorrhage, producing a more sustained proptosis.


Photograph obtained with the patient at rest

Conjunctival orbital varix in a 56-year-old man whose right eyelid bulges when straining

Photograph obtained during the Valsalva maneuver


Conjunctival orbital varix in a 56-year-old man whose right eyelid bulges when straining

Photograph obtained with the upper eyelid elevated


USUS• The distensibility of varices during the Valsalva maneuver .

• An intermittently anechoic retrobulbar lesion that exhibits intrinsic flow during the Valsalva maneuver is indicative of a varix.

• Color Doppler imaging may demonstrate a reversal of flow toward the transducer during the Valsalva maneuver.


CTCT• In supine position usually normal appearance or only mild enlargement of the involved veins.

• A maneuver that increases venous pressure (scanning in the prone position, jugular vein compression with a tourniquet, or the Valsalva maneuver) is required to demonstrate lesion distensibility.

• Varices may be smooth contoured, clublike, triangular, or segmentally dilated, or they may appear as a tangled mass of vessels.


CECT image obtained with the patient at rest

Bilateral orbital varices in a 27-year-old woman with a sensation of eye pressure when stooping to pick up her child

CECT image obtained with the patient at Valsalva maneuver


MRIMRI• Hypo- to hyperintense signal on T1WI.

• Hyperintense signal on T2WI.

• Usually enhance intensely after the administration of contrast material.


Axial T1-weighted MR image obtained with the patient supine

Orbital varix in a 33-year-old woman with proptosis when straining

prone

supine

CE T1-weighted fat-suppressed images

Venous Lymphatic Venous Lymphatic MalformationsMalformations

Venous Lymphatic malformationsVenous Lymphatic malformations( Lymphagioma )( Lymphagioma )

• Arise from the pluripotent venous anlage, which may develop into both venous and lymphatic structures.

• The lesions are sometimes referred to as no-flow or low-flow vascular malformations.

• They may be evident at birth, but they generally manifest in infancy or childhood (43% are diagnosed before the age of 6 years; 60%, before the age of 16 years).

•Overall, males and females are affected with approximately equal frequency.


• Although venous lymphatic malformations may enlarge slowly, producing progressive proptosis.

• Hemorrhages within these malformations often occur after minor trauma or infection and occasionally develop spontaneously.

•A spontaneous intralesional hemorrhage may pro-duce variable-sized chocolate-colored cysts that may cause acute proptosis, restriction of eye movements and, occasionally, optic nerve compression.

• Worsening proptosis during viral infections suggests that the more superficial and the larger its lymphatic component.



Venous lymphatic malformation in a 47-year-old woman with acute proptosis and restricted movement of the left eye


Venous lymphatic malformation in a 5-year-old girl

during an upper respiratory tract viral infection.

after the patient recovered from the viral infection


• Lymphatic malformations are unencapsulated, diffuse, and multicompartmental.

• Often including both intraconal and extraconal components.

• Orbital venous lymphatic malformations are isolated from the normal orbital vasculature and, unlike varices, are not affected by postural changes.

• However, they may be associated with intracranial vascular malformations, especially developmental venous anomalies.


Histologic analysis demonstrates delicate, bloodless, lymph-filled, endothelium-lined vascular channels of various luminal diameters. Intervening connective-tissue septa contain lymphocytes and fragile blood vessels (neovascular tufts) that are thought to be the sources of hemorrhage.


• Treatment is controversial and problematic.

• Depends on the growth, size, location, and morphology of the particular lesion.

• Observation and conservative management, when possible, are recommended.

• Surgery has been suggested for lesions that cause marked stretching or compression of the optic nerve or corneal compromise or impending amblyopia .

•Various alternative therapies have proved successful or promising, including the intralesional injection of sclerosing agents, fractionated beta irradiation, carbon dioxide laser ablation, and intralesional injection of steroids.


• Modality of choice : best depicts the various components.

• Signal intensity of the lesions depends on the type of fluid within the cystic components.

• T1WI best depict lymphatic or proteinaceous fluid.

• T1W fat-suppressed images are best for detecting blood products.

• T2W fat-suppressed images provide improved visibility of components that contain nonhemorrhagic fluid.

MRIMRI


• Contrast material does not provide significant additional information, but an absence of enhancement is indicative of a lymphatic component.

• Fluid-fluid levelsFluid-fluid levels produced by hemorrhages of various ages within multiple cysts are almost pathognomonicpathognomonic.

MRIMRI


Axial T2-weighted fat-suppressed MR image

Venous lymphatic malformation in an 11-year-old boy with progressive proptosis of the right eye and lateral displacement of the globe


Cystic components usually demonstrate low-level internal echoes, but an intracystic clot may be hyperechoic

USUS

CTCT

• Poorly circumscribed, multicompartmental, and heterogeneously hyperattenuating, and they enhance minimally after contrast material administration.

• Phleboliths may be present.


Axial unenhanced CT image

Venous lymphatic malformation in an 11-year-old boy with progressive proptosis of the right eye and lateral displacement of the globe

Arterial and Arterial and Arteriovenous LesionsArteriovenous Lesions

Arteriovenous FistulasArteriovenous Fistulas / Wyburn-Mason Syndrome / / Wyburn-Mason Syndrome / Carotid Cavernous Fistulas / Ophthalmic Artery Carotid Cavernous Fistulas / Ophthalmic Artery AneurysmsAneurysms

Arteriovenous FistulasArteriovenous Fistulas

• Arteriovenous fistulas that involve the orbit are rare.

• These lesions typically manifest with periorbital swelling, dilated retinal veins and epibulbar vessels, visible or palpable pulsations, an audible bruit, glaucoma and, occasionally, visual field defects due to ophthalmic artery steal syndrome.

• The pulsation and bruit can usually be diminished by compression of the ipsilateral common carotid artery.

Arteriovenous FistulasArteriovenous Fistulas

• US, CT with standard and angiographic protocols, and MR imaging with standard and angiographic protocols can help diagnose arteriovenous fistulas;

• However, conventional catheter-based angiography typically is required for precise definition and treatment planning.

• Treatment involves embolization and in some cases surgery.


Lateral projection from catheter-based angiography demonstrates early filling of a dural arteriovenousfistula (black arrow) fed by a dilated right ophthalmic artery (arrowheads). Intracranial venous drainageis faintly visible (white arrow). (b) Lateral projection from a later phase of the same angiographic examinationshows rapid filling of the large intracranial venous component of the malformation (arrows).

Orbital arteriovenous malformation in a 33-year-old man with proptosis and visible pulsations of the globe

Wyburn-Mason SyndromeWyburn-Mason Syndrome(Bonnet-Dechaume-Blanc)(Bonnet-Dechaume-Blanc)

• The Wyburn-Mason syndrome is an exceedingly rare oculocerebrocutaneous syndrome that consists of unilateral arteriovenous malformations of the visual pathways and midbrain.

• The syndrome is congenital, nonhereditary, and without race or sex predilection.

• It may occur with associated facial vascular nevi or telangiectasias.



Wyburn-Mason syndrome in a 16-year-old boy

Wyburn-Mason SyndromeWyburn-Mason Syndrome(Bonnet-Dechaume-Blanc)(Bonnet-Dechaume-Blanc)

• Symptoms are highly variable and depend on the size of the malformations.

• Patients may present with cosmetic facial deformity, headache, seizure, intracranial hemorrhage, optic atrophy, and, occasionally, pulsatile exophthalmos.

• Overall prognosis is poor.


Axial contrast-enhanced CT images

Wyburn-Mason syndrome in a 16-year-old boy

Carotid Cavernous FistulasCarotid Cavernous Fistulas

• Result from abnormal communication between the cavernous sinus and one or more branches of the internal or external carotid artery.

• Occur in middle to late adulthood and are more common in women.

• May result from direct trauma, surgery, dural sinus thrombosis, or atherosclerosis or may occur spontaneously.

• Spontaneous carotid cavernous fistulas have been reported in patients with Ehlers-Danlos syndrome, osteogenesis imperfecta, and pseudoxanthoma elasticum.

• Often manifest with the classic triadclassic triad of pulsatile exophthalmos, conjunctival chemosis, and an auscultatory bruit.



Right carotid cavernous fistula in a 67-year-old woman

Photograph shows conjunctival injection and mild p roptosis. The patient also had papilledema and a br

uit over the eye.


• However, a gradual decrease in visual acuity, with or without palsy of cranial nerves III, IV, V, and VI, may be the only sign.

• Secondary findings such as proptosis, congestive extraocular muscle enlargement, superior ophthalmic vein distention, and cavernous sinus dilatation are usually identified at CT or MR imaging

• Conventional catheter angiography is usually required for lesion classification and treatment planning before embolization.


Carotid cavernous fistula in a 52-year-old woman with proptosis, chemosis, and

conjunctival injection

Axial T2-weighted MR images

Axial maximum intensity projection image from MR angiography


Carotid cavernous fistulas may be classified on the basis of the source of their arterial supplysource of their arterial supply into the following four subtypes:

(a) main internal carotid artery

(b) dural branch of the internal carotid artery

(c) dural branch of the external carotid artery

(d) dural branches of both the internal and the external carotid arteries.

Ophthalmic Artery Ophthalmic Artery AneurysmsAneurysms

• Intracanalicular ophthalmic artery aneurysms are extremely rare.

• They arise at the origin of the ophthalmic artery from the supraclinoid internal carotid artery.

• Although they most often extend intracranially above the sella, they may sometimes extend into or through the optic may sometimes extend into or through the optic canalcanal.

• Lesions with a maximal diameter of 2–3 mm are usually asymptomatic, whereas those with a diameter of more than 3 mm may compress the artery or optic nerve or, if they rupture, cause intracranial subarachnoid hemorrhage.


CECT

Ophthalmic artery aneurysm in a 44-year-old woman with a subarachnoid hemorrhage


CT angiography

Ophthalmic artery aneurysm in a 44-year-old woman with a subarachnoid hemorrhage

TumorsTumors

Hemangioblastomas / Hemangiopericytomas / Hemangioblastomas / Hemangiopericytomas / Choroidal Hemangiomas / Choroidal Melanomas / Choroidal Hemangiomas / Choroidal Melanomas / MetastasesMetastases

HemangioblastomasHemangioblastomas

• Benign vascular tumor.

• Hemangioblastomas represent 1%–2% of all primary tumors of the central nervous system.

• Most hemangioblastomas that occur within the orbit are located in the retinaretina, although locations within the optic nerve have been reported.

• Ocular abnormalities due to a retinal hemangioblastoma are the earliest manifestations of von Hippel-Lindau von Hippel-Lindau diseasedisease in about 50% of cases.


•von Hippel-Lindau disease : an AD disorder that is localized to chromosome 3. It is characterized by both benign and malignant tumors).

• Ptients with a sporadic nonhereditary hemangioblastoma should undergo further evaluation for evidence of von Hippel-Lindau disease.


• Patients with a retinal hemangioblastoma are usually asymptomatic until the 3rd decade of life.

• A retinal hemangioblastoma may be a predisposing factor for retinal detachment, macular edema, and glaucoma.

• Early detection, followed by laser coagulation or cryotherapy, may prevent vision loss.

HemangiopericytomasHemangiopericytomas

• Rare.slowgrowing, highly vascular tumors.

• Relatively common in the musculoskeletal system (lower extremities), pelvis, and retroperitoneum.

• Approximately 15% of these tumors arise in the extracranial part of the head and neck, usually in the nasal cavity or paranasal sinuses.

• Origin within the orbit is rare.

• The tumors may occur at any time, from infancy through late adult life, although the mean ages at diagnosis in two large patient series were 45 years and 42 years.


• More common in males.

• Slowly progressive, sometimes painful proptosis and decreased visual acuity. Other symptoms include extraocular motility abnormalities, visual field deficits, and congestion of the retinal and choroidal vessels.

• Histologic findings range from benign to malignant characteristics, with many tumors demonstrating both.

• Although metastases are uncommon, they were reported in 15% of patients in one series, with the lung being the most common site.


• These mesenchymal tumors arise from the pericytes of Zimmerman, contractile cells that surround the outer aspect of small vessels and that are thought to regulate lumen size and produce collagen.

• Tumors are classified as sinusoidal, solid, or mixed.

• Histologic analysis demonstrates staghorn-like capillary spaces lined by plump, proliferating pericytes, with intervening fibrous septa.

• The classic staghornlike vascular pattern is not unique to hemangiopericytomas; it is encountered in a variety of other neoplasms, including synovial sarcomas, fibrous histiocytomas, and malignant peripheral nerve sheath tumors.



Hemangiopericytoma


• Hemangiopericytomas are usually lobulated, encapsulated, and well circumscribed, but they may have infiltrative margins.

• The typical location is extraconal; lesions commonly arise in the adjacent paranasal sinuses.

• The standard treatment is wide surgical excision.

• Postoperative irradiation is recommended for incompletely excised lesions. Local recurrence in approximately 30% of cases has been reported, and lesions may recur up to 30 years after initial treatment.


Axial contrast-enhanced CT

Hemangiopericytoma in a 47-year-old man with proptosis of the left eye


Moderately hyperechoic, with high vascularity on color doppler images, a feature that permits their differentiation from cavernous hemangiomas.

USUS

CTCT• Typically homogeneous and lobulated.

• May be : well circumscribed , irregular margins, osseous erosion ,involve the central nervous system.

• Hemangiopericytomas enhance intensely ( marked early arterial phase and early venous phase enhancement followed by rapid washout.)



Hemangiopericytoma in a 47-year-old man with proptosis of the left eye


MRIMRI

• The signal intensity is similar to that of gray matter on T1- and T2-weighted images.

• Digital subtraction angiography demonstrates a prominent arterial supply with an early florid blush and persistent tumor staining.

Choroidal HemangiomasChoroidal Hemangiomas

• These congenital vascular hamartomas typically manifest in middle-aged or elderly people (mean age, 31 years; age range, 7–58 years).

• The solitary or circumscribed choroidal hemangioma is a benign vascular neoplasm that is confined to the choroid, has distinct margins, and is typically located posterior to the equator of the globe.


• Asymptomatic circumscribed choroidal hemangiomas do not require treatment unless retinal detachment occurs. ( laser photocoagulation )

•The clinical appearance of the circumscribed choroidal hemangioma is that of a smoothly elevated, slightly dome-shaped, reddish-orange choroidal mass that blends with the surrounding choroid.


• CT is useful for diagnosis, but MR imaging is considered to provide depiction superior to that of CT.

• At CT, circumscribed choroidal hemangiomas in the absence of retinal detachment appear as ill-defined masses that exhibit intense enhancement after the administration of contrast material.

• At MR imaging, Most have a lenticular shape with a maximal diameter of 3–11 mm and signal that is hyperintense to that of vitreous on T1WI. On T2-weighted fast spin-echo images, the signal is hyperintense to that of vitreous. The lesions enhance intensely after the administration of contrast material.


CECT

Circumscribed choroidal hemangioma in an 8-year-old girl


Circumscribed choroidal hemangioma in an 8-year-old girl

Axial unenhanced T1WI Axial unenhanced T2WI

contrast-enhanced T1-weighted fat-suppressed

Choroidal MelanomasChoroidal Melanomas

• The most common primary intraocular tumors in adults

• Melanomas may occur in any of the three subdivisions of the uvea: the iris, the ciliary body, and the choroid.


• Most common among people of northern European descent and are uncommon among African American.

• 65% of melanomas occur in those older than 50 years.

• Patients may be asymptomatic and the lesion discovered during a routine ophthalmologic examination.

• Symptomatic patients may experience a vision loss, photopsia, and visual field deficits.


• Primarily metastasize to the liver, and some metastases manifest before primary tumor detection. Other sites of metastasis, in order of decreasing frequency, are lung, bone, kidney, and brain.

• Treatment selection depends on the site of origin (choroid, ciliary,body, or iris), size, and location of the primary lesion as well as whether extraocular extension, recurrence, or metastases are present.


• Large melanomas (10 mm thick) traditionally have been managed with enucleation.

• For medium-sized lesions (3–10 mm thick), plaque brachytherapy and external-beam radiation therapy have been accepted as alternatives to enucleation.

• Small tumors (3 mm thick) should be monitored every 3–6 months with US.

• Transpupillary thermotherapy was shown to be effective for small lesions, with fewer complications than radiation therapy and without the need for incisional surgery.


• CTCT provides a valuable method by which to demonstrate these lesions. ( Typically assessed with an ophthalmologic examination, fluorescein angiography, or US)

• Unenhanced CTUnenhanced CT : elevated, hyperattenuating, and sharply marginated.

• Contrast-enhanced dynamic CTContrast-enhanced dynamic CT : distinguish uveal melanomas from other lesions, such as choroidal hemangiomas, by providing information about vascularity and perfusion.

• Most choroidal melanomas appear as well-defined solid masses at MR imagingMR imaging.


• Those that are hemorrhagic or necrotic have varied MR imaging appearances.

• Because of the paramagnetic effects of Because of the paramagnetic effects of melanin, intensely melanotic melanomas have melanin, intensely melanotic melanomas have shorter T1 and T2 relaxation times,shorter T1 and T2 relaxation times, producing producing increased signal intensity on T1-weighted increased signal intensity on T1-weighted images and mark-edly decreased signal images and mark-edly decreased signal intensity on T2-weighted images.intensity on T2-weighted images.

• Among ocular tumors, only Teaching Point melanomas manifest these signal intensity characteristics.

• Unfortunately, amelanotic and slightly melanotic melanomas do not show the same signal intensity characteristics.


• Instead, the signal in these lesions may appear isointense on T1-weighted images and only slightly hypointense on T2-weighted images, similar to that in choroidal metastases and other tumors of the globe.

• Following the administration of contrast material, choroidal melanomas demonstrate moderate to strong enhancement.

• Contrast-enhanced fat-suppressed MR imaging also may demonstrate scleral invasion, tumor extension to the optic disc, and extraocular invasion.

Axial contrast-enhanced T1-weighted fat-suppressed image


Choroidal melanotic melanoma in a 51-year-old man with decreasing vision in

the left eye

Coronal T2-weighted MR image

MetastasesMetastases

• Uveal metastasesUveal metastases typically reach the globe via the posterior ciliary arteries and, therefore, commonly involve the posterior half of the globeposterior half of the globe.

• The primary lesions that are the most common most common sources of uveal metastases are breast and sources of uveal metastases are breast and lung carcinomaslung carcinomas. (also may involve extraocular muscles)

• MR imaging is superior to CT for MR imaging is superior to CT for distinguishing uveal metastases from uveal distinguishing uveal metastases from uveal melanomas.melanomas.



Choroidal metastasis from stomach carcinoma in a 55-year-old man

Axial T1-weighted MR imageAxial T2-weighted MR image

Axial contrastenhanced T1-weighted fat-suppressed MR image

Coats DiseaseCoats Disease

• An idiopathic primary vascular anomalyprimary vascular anomaly of the the retinaretina.

• Characteritic : retinal telangiectasiasretinal telangiectasias and exudative exudative retinal detachmentretinal detachment

• Caused by : an accumulation of lipoproteinaceous exudate in the retina and subretinal space. ( unknown pathogenesis )

• Because of retinal detachment, children often present with leukokoria, and the disease may be difficult to clinically differentiate from retinoblastoma.

• Although the disease is present at birth, signs and symptoms are delayed until retinal detachment produces loss of vision, typically between the ages of 6 and 8 years.

• Boys are affected approximately twice as often as girls.


• USUS : may demonstrate retinal detachmentretinal detachment and particulate echoes from subretinal material, presumably cholesterol crystals.

• CTCT : findings include a normal-sized globe with increased overall attenuation due to the density of the subretinal exudate. CT also may demonstrate the retinal detachment.

• Important for the distinction of Coats disease from retinoblastoma is the fact that true calcificationstrue calcifications are common in retinoblastomas but occur rarely, if ever, in association with Coats disease.


• MR imagingMR imaging : the signal intensity of the globe in Coats disease is somewhat variable, depending on the proportions of proteins and lipids.

• Most often, there is diffuse signal hyperintensity on both T1- and T2-weighted images.

• After the administration of contrast material, enhancement is visible along the leaves of the detached retina and at the sites where the retina inserts.

• The absence of an enhancing mass helps distinguish Coats disease from retinoblastoma, persistent hyperplastic primary vitreous, and toxocaral endophthalmitis.


• If the disease is detected in its early stagesearly stages, photocoagulation or cryotherapy may be used to obliterate the telangiectases.

• In later stageslater stages of the disease, neovascularity of the iris often causes neovascular glaucoma with resultant blindness or severe eye pain, necessitating enucleation.

SummarySummary• Vascular lesions of the orbit are confusing entities with imaging features that may overlap.

• Diagnosis requires an understanding of the classification of vascular lesions, integration of the individual patient’s history with epidemiologic data, and familiarity with the imaging features that are typical of specific lesions.

• The use of appropriate imaging techniques (eg, delayed contrast-enhanced imaging for cavernous malformations, prone imaging for orbital varices) and recognition of pathognomonic features (eg, multiple fluid-fluid levels in lymphatic malformations, progressive delayed enhancement in cavernous malformations) are often essential for precise diagnosis.

Education

Vascular Lesions Of The Orbit