Ординатура / Офтальмология / Английские материалы / Ophthalmic Ultrasound A Diagnostic Atlas 2nd edition_ DiBernardo, Greenberg_2006

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Figure 6–11 Intraocular foreign body/metallic. (A) Transverse B-scan showing dense vitreous opacities (V) and a highly reflective signal that appears to be embedded in the globe wall (arrow) with shadowing in the orbit (S). (B) Longitudinal scan showing the peripheral location of the foreign body (arrow) and the shadow being produced (S). (C) Standardized A-scan showing a significant spike (arrow) produced by the foreign body and decrease in the spike (S) from the orbit consistent with shadowing.

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Figure 6–12 Intraocular foreign body (IOFB)/metallic. (A)

Vertical axial scan showing a large metallic foreign body in the globe, inferiorly (arrow). (B) Longitudinal scan showing the anterior location of the foreign body (arrow). (C) A-scan from the region of the foreign body. The first spike (arrow) is the IOFB. Most of the sound is being absorbed by the foreign matter, causing shadowing/decrease in the height of the orbital signals.

Figure 6–13 Intraocular foreign body/spherical. Spherical foreign bodies (e.g., BBs) produce an artifact known as a “comet tail” (arrows).

Figure 6–14 Trauma/disorganized globe. There are occasions when severe trauma makes differentiation of intraocular pathology impossible. In cases like this, it may be helpful to perform serial ultrasounds as the hemorrhage and swelling begin to dissipate.

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Figure 6–15 Trauma/orbital hemorrhage. This patient was involved in a motor vehicle accident and presented with proptosis and severe pain. The globe was intact. However, echographically a large orbital hemorrhage was detected. (A) A transverse orientation displays an echolucent lesion in the orbit (H) compressing the globe slightly; note the flattening of the globe wall. (B) Longitudinal orientation showing the large radial extent, from anterior (A) to posterior (P). (C) Standardized A-scan taken at the orbital setting showing the borders of the clot (bright spots) and the low reflectivity (arrow), consistent with fresh hemorrhage. (From DiBernardo C, Joseph D, Miller N. Radiographic and echographic imaging studies. In: MacCumber MW, ed. Management of Ocular Injuries and Emergencies. Hagerstown, MD: Lippincott-Raven; 1998. Reprinted by permission.)

Many intraocular tumors are easily distinguishable from one another ophthalmoscopically when the media is clear. Some mimic one another and are more difficult to diagnose, and if the media is not clear, ophthalmoscopic differentiation may be impossible. Standardized echography can play an important role in confirming the diagnosis, obtaining accurate measurements of newly discovered lesions, and monitoring changes that may occur over time. Information concerning the patient’s history, as well as the clinical findings such as location, pigmentation, and presence of vitreous hemorrhage and/or retinal detachment are all useful pieces of information for the echographer. For instance, if hemorrhage is present in the vitreous or beneath the retina, the likelihood of a lesion being a metastatic carcinoma is diminished.

Echographically, intraocular tumors display different acoustic characteristics because of their vastly different histopathologic compositions. These distinguishing features are most appreciated with the standardized A-scan at the tissue sensitivity setting. The

B-scan is most useful in determining the topographic features of tumors, such as shape, location and extension. The basal diameter is determined using both transverse (lateral dimension) and longitudinal (radial dimension) scans. Sometimes gross estimation of the height can also be performed using contact B-scan, but the standardized A-scan provides the most accurate measurements from the surface of the tumor to the inner sclera. The structure (distribution of cells), the reflectivity (size of the cells), and the presence or absence of vascularity can be appreciated best with the standardized A-scan.

The typical echographic features of intraocular tumors and pseudotumors are described in Table 7–1. Keep in mind that sometimes a lesion’s characteristics do not conform to what is considered typical. In these cases, it is important for the echographer to note any atypical features and correlate these findings to the clinical history and appearance. On the following pages are selected cases of intraocular tumors with descriptions of the echographic findings.

Suggested Readings

Byrne SF, Green RL. Second Edition: Ultrasound of the Eye and Orbit. St. Louis: Mosby Yearbook; 2002

Farah ME, Byrne SF, Hughes JR. Standardized echography in uveal melanomas with scleral or extraocular extension. Arch Ophthalmol 1984;102:1482–1485

Harbour JW, Murray TG, Byrne SF, et al. Intraoperative echographic localization of iodine 125 episcleral ra-

dioactive plaques for posterior uveal melanoma. Retina 1996;16:129–134

Schachat AP, DiBernardo C. Management of a patient with a small choroidal melanoma. Wilmer Retina Update 1995;1:13–16

the height of the internal spikes. (D)

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A-scan at measuring sensitivity.

Figure 7–6 Collar button. This patient was a monocular, mentally handicapped man whose caregivers noticed a decrease in his ambulatory level. Clinically, he had a dense cataract. (A) Echographically, there was a massive collar button–shaped tumor. (B) The internal structure was typical for melanoma.

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Figure 7–8 Diffuse melanoma. (A) Transverse image showing the large lateral extent of this diffuse melanoma. (B) Longitudinal scan. (C) Although the lesion is not very elevated, which is usually the case in diffuse lesions, the reflectivity is low (arrow).

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Figure 7–9 Lobulated. (A) In transverse (cross-section) view the tumor appears to be dome-shaped (arrow). (B) The longitudinal scan showing that it is actually bi-lobed (arrows). (C) A-scan showing low reflectivity (arrow).