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OCULAR ULTRASOUND. RMG: Mar,2018. @KIJOHS. Sonography of the eye.
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OCULAR ULTRASOUND RMG: Mar,2018. @KIJOHS
Sonography of the eye • Cystic nature of the eye, superficial location, and high frequency transducers make it possible to clearly show normal anatomy and pathology such as tumors, retinal detachment, vitreous hemorrhage, foreign bodies, and vascular malformations. • Sonography is used more commonly by ophthamologists to evaluate the eye particulalry when direct examination by sit-lamp and funduscopy is not sufficient. • Detailed cross section anatomy of the entire globe is possible with conventional sonographic equipment. • Anterior chamber visualization requires a dedicated sonographicbiomicroscope.
Sonography of the eye • Color Doppler and A-mode sonography are reported to be useful in characterizing masses. • The sonography examination is rapid and cost-efficient, without the contraindications, such as pacemakers, the MRI has. • Sonography avoids the irradiation associated with CT and the need for sedation in children. • Therefore it can be used repeatedly during treatment of tumors to assess response to therapy.
technique • Conventional gray-scale sonographic equipment and 7-15MHz transducers are used , scanning through the eyelid • A dedicated ocular sonographicbiomicroscope using frequencies up to 50MHz can be used • Instructions to patient, rotating eyeball when needed • Tegaderm over the eye with Stand off pad of gel • Image at least in two planes
Normal anatomy • The cornea, conjunctiva,anterior chamber, posterior chamber and iris rarely require sonography, but they are excellently detailed with newer sonographicbiomicroscopes. • The lens is best inspected directly with no need for sonography • A mature cataract of the lens may obscure the retina on funduscopy, necessitatin sonography • The vitreous body is gelatinous and anechoic, with loose attachments to the retina, and it stabilizes the eyeball. • The choroid is part of the uveal tract, which also includes the ciliary body and the iris, and is the site of many intraocular tumors.
Normal anatomy • The choroid has a rich vascular supply from the long and short posterior ciliary arteries. • Because the retinal is pigmented, direct inspection of the choroid by funduscopy is limited, and sonography plays an important role in diagnosing choroidal melanoma and metastatic tumors. • The retina and choroid are sonographically perceived as one layer in the normal eye, the sclera is highly reflective outer layer • The retina has a rich blood supply from the central retinal artery, which is clearly seen on color Doppler sonography as are the adjacent posterior ciliary arteries that supply the choroid and optic disc.
Normal anatomy • The optic nerve is visible sonographically as a hypoechoic ban starting at the scleral zone and extending posteriorly and medially
Pathology • Commonly seen ocular pathologies • Retinal detachment • Vitreous hemorrhage and vitreous detachment • Elevated ICP • Globe rapture • Hyphema • Lens dislocation • Melanoma • Retinoblastoma • Foreing bodies • Retrobulbar hematoma • Rhabdomyosacoma • Hemangioma • Persistent hyperplastic primary vitreous (PHPV aka PFV) - Rare
Pathology • Axial cross-section of eye and diagrammatic representation of pathology. • C = cornea, A = anterior chamber, L = lens, V = vitreous body, CH = choroid, CB = ciliary body, I = iris, R = retina, S = sclera, CRA = central retinal artery, ON = optic nerve, PCA = posterior ciliary arteries. • Sonographicanatomic correlation is shown in Figure on previous slide.
Lesions of the iris • Cystic or solid lesions of the iris are difficult to show on conventional equipment but are well detailed on dedicated ultrasound biomicroscopicimaging. This equipment, operating at 50 MHz or sometimes higher, has a resolution of 30 μm, far in excess of CT or MRI
Retinal Detachment • Retinal detachment is a separation of the neurosensory retina from the underlying pigmented layer. • This condition can be asymptomatic for a long time, then presents with flashes of light, floaters, “black rain” (if there is accompanying vitreous hemorrhage), a dark shadow, or loss of visual acuity, depending on the exact location and severity of the detachment. • The three types are based on the cause: • Rhegmatogenous detachment—that is, associated with a retinal tear—is the most common type and is seen with advancing age, a familial disposition, and associated myopia. • Tractional detachment originates in adjacent vitreous strands. • Exudativedetachment is due to fluid, blood, or lipids behind the neurosensory retina and can be associated with tumors of the choroid.
Retinal detachment • Risk Factors. • Increased age • Myopia • Cataract surgery • Diabetes • Sickle cell disease • Trauma
Retinal detachment. Sonographic features • Short, reflective, linear structure protruding into the vitreous • Membrane that floats into vitreous • Attached at optic nerve head
42-year-old man with retinal detachment. Sonography shows severe posterior, central detachment (arrow).
Vitreous Hemorrhage • Vitreous hemorrhage spreads diffusely in the gelatinous vitreous, obscuring the optic disk, and does not form a fluid meniscus unless the bleeding is in the space around the vitreous. • The causes of vitreous hemorrhage include; • vitreous detachment, • diabetic retinopathy, • retinal microaneurysm, • trauma, and • vascular tumor • The patient complains of “black rain” and has reduced visual acuity. • The hemorrhage is absorbed slowly, and the clinical course depends on the exact cause. • If choroid tumors are large or near the optic disk, enucleation of the eye is sometimes necessary. However, brachytherapy—that is, radiation plaques placed outside the sclera adjacent to the tumor—is the preferred mode of treatment
Vitreous HemorrhageBleeding from fragile vessels in vitreous space. • Risk factors • Diabetes • Trauma • Retinal tears • Symptoms • Floaters • Flashes • Cloudy vision • Often unilateral
Vitreous pathology • Vitreous hemorrhage – more common in diabetes • Vitreous detachment – vitreous becomes more solid with time and may congeal into mass • Vitreous pathology may be confused with retinal detachment • Kinetic exam – “clothes dryer tumbling” motion of vitreous material as often free floating in eye
Elevation of ICP • Optic nerve sheath – direct communication with the brain • Increased ONSD is an indicator of elevated ICP • ONSD < 5mm rules out elevated ICP in adults • Measure 3 mm posterior to the globe • Normal values vary by age • < 5mm in adults • < 4.5mm in children (1-15 yo) • < 4mm in children (< 1 yo) • Enlarged ONS consistent with elevated ICP
PHPV – Persistent Hyperplastic Primary Vitreous. • Rare congenital development malformation of the eye • Manifests as unilateral or bilateral leucocoria • Patients may have poor vision, small eye (microphthalmia) and strabismus • An echogenic band may be seen in the posterior segment of the globe extending from the posterior surface of the lens to the optic nerve head • On color Doppler, arterial blood flow may be seen within this band
Malignant melanoma • Malignant melanoma is the most common primary intraocular tumor and occurs more often in the choroid than in the iris or ciliary body. Iris melanomas can cause secondary glaucoma. • Ciliary body melanomas may cause changes in accommodation from lens displacement. • Choroidal tumors present with decreased visual acuity and visual field defects. A small melanoma of the ciliary body can be missed if funduscopy is performed without depressing the sclera externally. • Melanomas of the eye are usually rounded, hypoechoic, and very vascular. They can be complicated by retinal elevation and vitreous hemorrhage
52-year-old woman with choroidal melanoma.A, Typical sonographic features include hypoechoic mass, lobular in shape, with marginal retinal elevation (large arrow). Hyperechoic rim is combination of elevated retina and peripheral blood vessels. B, Funduscopy shows large dark melanoma with peripheral retinal elevation, which appears translucent yellow because red color of underlyingchoroid, seen elsewhere, is lost.
5-year-old woman with ciliary body melanoma.A, Sonogram shows tumor is large and round, which is common for melanoma. C = ciliary body, A = anterior chamber.B, Color Doppler sonogram shows blood vessels encircling and penetrating tumor.C, Ophthalmoscopy shows dark tumor partiallyobscuring normal “red reflex” of retinochoroidal pigmentation seen through dilated pupil.
62-year-old man with melanoma (arrow) arising from ciliary body (C), which is small and buttonlike. Smallmelanomaof ciliary body can be missed because of its small size and location if funduscopy is performed without depressing sclera externally.
Complication of melanoma • Complications of melanoma in 56-year-old man with blurred vision. • Retinal elevation (small arrows) is caused by tumor mass (large arrow) or by possible transudation of fluid.
Complications of melanoma • Complications of melanoma in 69-year old woman with diminished brightness of vision. • Vitreous hemorrhage, seen as low-level echoes filling vitreous body (V), completely obscures direct view of tumor (arrow) by funduscopy.
Complications of melanoma • Complications of melanoma in 42-year-old man with severe loss of vision in one eye. • Location of melanoma (large arrow) on and adjacent to optic disk (small arrows) may prevent radiation treatment and could necessitate enucleation of eye.
55-year-old man with choroidal melanoma.A, Melanoma (M) b4 brachytherapy (radiation plaque treatment). Melanoma is biconvex, with slight elevation of retina (arrow) at one margin coz of serous fluid transudate.B, After radiation plaque treatment, tumor (M) shows significant decrease in volume. Apical tumor dimensions can be obtained using A-mode sonography
Metastasis and lymphoma • Metastasis to the choroid is most common from the breast, lung, and unknown primary sites. • Metastatic tumors are discoid in shape and hyperechoic compared with melanoma. • A-mode sonography shows the difference in echogenicity (also called “reflectivity” in ophthalmology literature) between melanomas and metastases. • Lymphoma can occur in isolation or as metastasis to the choroid or the vitreous body
50-year-old woman with primary breast cancer metastasizing to eye. • Although flat hyperechoic tumor (long arrow) is morphologically similar to lymphoma or treated melanoma, its surface is more irregular, and A-mode sonography (tracing at bottom) shows high reflectivity (short arrows).
67-year-old man with metastatic adenocarcinoma from unknown primary site.A, Tumor is flat hyperechoic mass (arrows), well seen sonographically in nasal field of rotated eyeball.B, MR image shows subtle, isointense flat mass in nasal aspect of right eye (arrow), which is best seen on this T1-weighted image;
38-year-old woman with lymphoma. • Sonography depicts rather flat mass of moderate echogenicity (long arrow). • A-mode sonographic tracing, taken through black-line axis, shows moderate reflectivity (short arrows) that iSs greater than that of melanoma (low reflectivity) but less than that of metastasis (high reflectivity).
rhabdomyosarcoma • Rhabdomyosarcoma is the most common primary malignancy of the orbital cavity in children, presenting with proptosis, inflammation, and loss of vision. • A combination of radiation and chemotherapy makes a cure possible in many cases. • Sedation for repeated CT or MRI during follow-up can be avoided by using sonography
2-year-old boy with rhabdomyosarcoma of extraocular muscle. • A, Hypoechoic, conical tumor (short arrows) is seen posterior to eye and slightly superior to optic nerve (long black arrow). Retinal detachment is also present (white arrow).Advantages of sonography in this infant outweigh those of MRI because sedation can be avoided with minimal loss of anatomic information
2-year-old boy with rhabdomyosarcoma of extraocular muscle. • .B, Color Doppler sonogram shows that despite tumor infiltration around optic nerve (arrows), blood flow through central retinal artery (CRA) and posterior short ciliary arteries(PCA) is intact.
Hemangioma • Hemangioma is the most common benign tumor of the orbital cavity and can be capillary (in children) or cavernous 37-year-old man with hemangioma of orbit. A, Nasal superior location is common, as seen on this sonogram, which shows superior ophthalmic vein (black arrow) draining hemangioma (white arrows).
B, IV contrast-enhanced CT scan of orbits shows prominent draining vessels (arrows) more clearly than sonogram, but repeated irradiation from CT during follow-up can be avoided by using sonography. • C, Color Doppler sonogram shows blood flow of mixed color (arrows), indicating some turbulence in larger vessels of hemangioma in medial aspect of image. • Draining ophthalmic vein seen on gray-scale images and CT is not visible, presumably because of low-velocity flow.
Retinoblastoma • Retinoblastoma is the most common primary intraocular malignancy of childhood often occurring before the age of 3 years, and presenting with a white pupil (leukocoria) and strabismus. • Retinoblastoma is quite vascular and can invade the vitreous body.
1-year-old girl with retinoblastoma.A, Irregular shape of tumor (short arrows) is hard to outline on this sonogram, but hyperechoic calcific foci (long arrow) are characteristic of retinoblastoma.B, Large retinoblastoma is cream-colored on funduscopic image and partly overlies optic disk (arrow).
Microphthalmos and Coloboma • Microphthalmos and coloboma are congenital anomalies caused by incomplete fusion of the optic cup in the sixth week of pregnancy. • They cause a posterior eyeball defect with a posterior orbital cyst and an abnormally short eye
37-year-old man with microphthalmos and coloboma.A, Axial left-to-right sonogram shows abnormally short length of eye (double arrow), posterior defect or coloboma (single arrow), and cyst (C) behind eye.B, Abnormality, particularly cyst (C), is better detailed on axial MR image although coloboma is clearer on sonography
Foreign bodies • Foreign bodies can be metallic, plastic, or wood. • The bodies usually lodge in the conjunctiva or cornea, and the diagnosis is made by direct examination. • Occasionally penetrating through the cornea, metallic foreign bodies may lodge anywhere up to the retina and can cause severe inflammation and infection.
32-year-old male iron foundry worker with foreign body in eye, whichappears as hyperechoic focus (arrow) in vitreous body of eye.
