orbit and visual pathway imaging strategies jalal jalalshokouhi-m.d. [email protected]
TRANSCRIPT
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
