Orbit and Visual Pathway imaging

strategies

Jalal JalalShokouhi-M.D.

jalaljalalshokouhi@hotmail.com

Orbit

• Configuration of orbital cone •

Contents:

- Globe (positio; size, density,

wall thickness)

- Eye muscles (position, course, density, width)

- Optic nerve (course, width)

- Ophthalmic vein (course, width)

• Checklist• Orbits• • Symmetrical •• Normal size •• Normal orbital cone• Orbital walls• • Smooth, sharp borders • • No bone destruction •• No circumscribed widening of bone or

softtissue• components

Globe

• Position •

Symmetry •

Size •

Spherical

Ocular contents • Density

Ocular wall

• Borders (smooth and sharp) •

Uniform thickness

Optic nerve

• Normal caliber •

Course

Eye muscles

• Position •

Width •

Course

Retrobulbar fat • Clear •

No masses

Ophthalmic vein • Course •

Caliber

Lacrimal gland • Size •

Symmetry •

No unilateral or bilateral enlargement •

Position

No excavation or destruction of adjacent bone •

Homogeneous internal structure •

No hypodense areas •

Smooth borders

Neurocranium

• Temporal lobes •

Frontal lobes

Paranasal

• Maxillary sinuses

sinuses

• Ethmoid cells

• OrbitsOrbits

• • Shape (orbital cone) •

• Size •

• Symmetry •

• Orbital walls:Orbital walls:

• - Borders (smooth and sharp)

• - No bone destruction

• - No circumscribed expansion of bony or softtissue

• components of the orbital wall

• Globe• • Shape (spherical) •• Size • Position • Symmetry •• Ocular contents:• - Signal intensity (fluid-equivalent) •• Ocular wall:• - Borders (smooth and sharp)• - Thickness •• Retrobulbar fat (clear) •• No masses

• Optic nerve

• • Caliber

• Course

• Eye muscles

• • Position •

• Width Course

• Ophthalmic vein • Course •

• Caliber

• Lacrimal gland

• • Size •

• Symmetry •

• No unilateral or bilateral enlargement •

• Position

• No excavation or destruction of adjacent bone •

• Homogeneous internal structure •

• No hypointense or hyperintense changes •

• Smooth borders

Neurocranium• Temporal lobes •Frontal lobesParanasal sinuses • Maxillary sinuses •Ethmoid cells

Exophtalmus

Differential Diagnosis: Orbital Swelling• Orbital infection (bacterial, viral, fungal)

• Orbital inflammation: orbital pseudotumor; granulomatous diseases (sarcoid,

Wegener's granulomatosis); vasculitides, connective tissue disorders

Diagnosis

Orbital cellulitis (serratia isolated on culture)

Differential Diagnosis: Lacrimal Gland Mass• Lymphoid/Inflammatory: acute (viral, bacterial,

orbital pseudotumor, lymphoma)or chronic (sarcoid, Wegener's, thyroid

opthmalopathy, Sjbgrens's syndrome,Mickulicz syndrome)• Epithelial neoplasms: pleomorphic adenoma or

malignant tumors (adenoid cysticcarcinoma, mucoepidermoid carcinoma,

adenocarcinoma)DiagnosisLacrimal gland enlargement due to acute

dacroadenitis

Differential Diagnosis: Enlargement of theExtraocular Muscles• Infection (bacterial, viral or fungal)• Thyroid orbitopathy• Inflammatory conditions: orbital pseudotumor, Sjogrens's

syndrome, Mickulicz'ssyndrome, granulomatous conditions (sarcoid, Wegener's

granulomatosis), connectivetissue disorders (rheumatoid arthritis, lupus, scleroderma),

retained foreignbodies• Vasculitides (PAN, giant cell arteritis)• Tumors: hemangioma, rhabdomyoma, plasmacytoma,

lymphoma, leukemia, rhabdomyosarcoma• AmyloidosisDiagnosisOrbital pseudotumor

Differential Diagnosis: ExtraocularMuscle Enlargement• Endocrine• Thyroid ophthalmopathy• Acromegaly• Inflammatory• Pseudotumor• Infection: bacterial, fungal, parasitic (cysticercosis, trichinosis)• Plasma cell granuloma• Sarcoid• Neoplastic• Benign: rhabdomyoma• Malignant: lymphoma, rhabdomyosarcoma, metastatic disease• Vascular• Carotid cavernous fistula• Extradural arteriovenous fistula• Deposition diseases: amyloid

DiagnosisThyroid orbitopathy

Differential Diagnosis: DiffuseHyperintensity in the Extra- and IntraconalFat on FAT SAT TIWI• Artifactual: artifact due to failure of fat

suppression• Pathologic: orbital pseudotumor, orbital cellulitis,

orbital neoplasm

DiagnosisArtifact due to asymmetric failure of fat-

suppression

Differential Diagnosis: Optic NerveEnlargement and Enhancement(Optic Neuritis)• Demyelinating disease': multiple sclerosis• Inflammatory: collagen vascular disease, orbital

pseudotumor, sarcoid• Infectious: HIV-related optic neuropathies, tuberculosis,

fungal infection, toxoplasmosis,syphilis• Neoplastic': optic glioma, optic nerve meningioma,

metastasis, leptomeningealcarcinomatosis• Vascular': ischemic neuropathy (severe hypertension,

systemic vasculopathies)• Others: radiation induced optic neuropathy, optic nerve

traumaNote: ' indicates that the process is usually unilateral.

Diagnosis

Radiation-induced optic neuropathy

Differential Diagnosis: RetrobulbarIntraconal Mass• Hemangioma• Schwanoma• Metastasis• Pseudotumor• Meningioma• Hemangiopericytoma• Lymphangioma• Varix• Hematic cyst

DiagnosisCavernous hemangioma

Differential Diagnosis: Enlargement of the

Optic Nerve or Sheath

• Tumors: optic nerve glioma, optic nerve meningioma, optic nerve neuroma, lymphoma,

leukemia (chloroma), metastasis (hematogeneous: breast and lung, direct invasion:

retinoblastoma, uveal melanoma), hemangioblastoma, hemangiopericytoma

• Inflammatory lesions: orbital pseudotumor, optic neuritis, sarcoidosis

• Others: pseudotumor cerebri

Diagnosis

Intraorbital meningioma

Differential Diagnosis: Choroidal Mass• Melanoma• Hemangioma• Hemorrhage• Retinal/choroidal detachment• Choroidal metastasis• Sarcoidosis• Retinal cyst• Retinoblastoma• Retinal gliosis• Nevi• Leiomyoma• Schwanoma• NeurofibromaDiagnosisChoroidal (uveal) melanoma

Differential Diagnosis: Intraocular Massin a Child• Neoplastic conditions: retinoblastoma and

retinocytoma", uveal melanoma,metastases (neuroblastoma, most common),

pseudoglioma (retinal astrocytomaor astrocytic hamartoma)• Nonneoplastic conditions: persistent hyperplastic

primary vitreous (PHPV),retinopathy of prematurity or retinal dysplasia

(ROP)", Coat's disease, toxocariasisor larval granulomatosis", chronic retinal

detachment", uveitisDiagnosisRetinoblastoma