Estimated to affect about 2500 adults every year in the United States, uveal melanoma is an aggressive condition that may affect the iris, ciliary body, and/or choroid. Approximately 50% of patients with ocular melanoma will develop metastases 10 to 15 years after diagnosis.1 Metastatic disease usually involves the liver and is nearly always fatal within 1 year despite therapy.

One of the main challenges associated with uveal melanoma is early detection because the condition is usually asymptomatic until the tumor grows large enough to disturb vision.2 Further, because this tumor is relatively uncommon, many ophthalmologists will see only a few cases during their entire careers. Ultrasonography can be a valuable aid to tumor detection and diagnosis and is also useful for selecting and planning therapy and for assessing the tumor response to treatment.

DIAGNOSTIC TOOLS

Most uveal melanomas are reliably diagnosed on the basis of a clinical examination using the slit lamp combined with indirect ophthalmoscopy (IO) through a welldilated pupil.3,4 Some small melanomas, however, may be difficult to differentiate from nevi. A number of ancillary tests may therefore be employed, such as optical coherence tomography (OCT), fundus autofluorescence imaging, and biopsy.3,4 Ultrasonography is widely regarded as an important ancillary test in the diagnosis of uveal melanoma.4 For example, with melanomas that have perforated Bruch membrane, ultrasonography shows the tumor to have a collar-stud or mushroom appearance, which is virtually pathognomonic. Furthermore, the internal acoustic reflectivity of a tumor, as illustrated by ultrasonography can provide an indication of the diagnosis. B-scan imaging of the posterior segment is particularly useful in identifying pathology that is not visible on ophthalmoscopy or OCT because of opaque media, for example in patients with cataract or vitreous hemorrhage. B-scan imaging can also reveal the presence of extraocular tumor extension into the sclera or orbit.

Ultrasonography produces high-quality images that allow the ophthalmologist or ocular oncologist to measure tumor dimensions and to determine the contour, vascularity, and extent of the tumor. Such information is invaluable when selecting treatment, planning radiotherapy, and assessing the tumor response afterwards. Furthermore, with high-frequency ultrasonography it is possible to obtain high-quality images of anterior segment tumors in the iris and ciliary body imaging areas that are not visible with OCT.5

The Eye Cubed diagnostic ultrasound system (Ellex) is considered to be one of the premier devices for ultrasound examination of the eye and is widely used in ocular oncology. It offers customized configuration of A-scan and B-scan modes, making it a suitable option for both retinal subspecialists and anterior segment surgeons. Cataract surgeons benefit from the inclusion of an immersion A-scan feature, which eliminates corneal compression and transmits ultrasound waves through dense cataract. Furthermore, the 40 MHz UBM widefield anterior segment B-scan mode gives ophthalmologists an unprecedented view of the lens apparatus, including zonules and ciliary muscles (areas that are almost impossible to visualize with other ultrasound systems). The 10 MHz posterior B-scan mode allows visualization of deeper tissue structures in the posterior segment. Such level of detail is possible thanks to the Eye Cubed's signal-to-noise ratio, which minimizes noise and allows the system to detect echoes from some of the smallest ocular structures. The Eye Cubed also features real-time high-resolution imaging and advanced movie mode using the fastest sampling rate available. It also has an internal memory for storing scans and is DICOM compatible, so data can be easily cross-referenced with patient details and transferred to an electronic medical record to optimize practice management.6

PERSONAL EXPERIENCE

One of us (BD) has used the Eye Cubed for more than 20 years, first at the Liverpool Ocular Oncology Centre in England and, more recently, at the Ocular Oncology Service of the University of California, San Francisco. This equipment has proved invaluable for diagnosis, treatment planning, and tumor monitoring. To follow are some cases in which the Eye Cubed proved particularly helpful.

Case No. 1. Using the Eye Cubed, we were able to identify a very rare extraocular local recurrence adjacent to the optic nerve following plaque radiotherapy of a medial choroidal melanoma in the right eye. Precise ultrasonographic measurements of tumor dimensions and distance from optic nerve enabled accurate proton beam radiotherapy, successfully conserving the eye with good vision (Figure 1).

Case No. 2. Figure 2A shows a dome-shaped melanoma superior to the right optic disc. Longitudinal and transverse B-scans provide accurate measurements (Figures 2B and 2C). A-scan ultrasonography demonstrates typical internal acoustic reflectivity (Figure 2D).

Case No. 3. Figure 3 shows a small peripheral cilary body mass lesion. The dimensions and extent of the lesion were well demonstrated with the Eye Cubed's B-scan probe.

Case No. 4. Figure 4A shows a superotemporal choroidal hemangioma in the right eye of a 9-year-old boy. EyeCubed A- and B-scans show high internal reflectivity consistent with this diagnosis (Figure 4B and 4C).

KEY CONSIDERATIONS

The Eye Cubed is a whole-eye solution to ultrasound imaging, with a wide range of scans and adjustments. It is, however, essential for the examiner to have proper training on how to use the technology correctly. Without adequate expertise, it is difficult to get the best out of any machine, but this is particularly true with ophthalmic ultrasound. There is also a danger of misinterpreting the information provided, resulting in an incorrect diagnosis. When planning treatment or assessing tumor growth or regression over time, it is essential to measure tumor dimensions accurately and consistently. For example, when measuring tumor thickness, it is important to identify the interface between tumor and sclera and essential to measure the thickest part of the tumor with the probe held perpendicular to the internal scleral surface. Without good technique, the examiner may conclude that the tumor has grown and send the patient for emergency treatment, thus causing the patient unnecessary distress and perhaps inappropriate therapy. Further, although many ophthalmologists have great faith in ultrasonography as a method of diagnosing ocular tumors, the use of ancillary tools to support or confirm a diagnosis should not be ruled out. For example, if a particular diagnosis is unclear, or if a patient presents with a rare condition, a biopsy may be necessary to ensure a correct diagnosis.

CONCLUSIONS

Ultrasound imaging is an important tool in ocular oncology and is increasingly regarded as the most important ancillary test, after slit-lamp examination and ophthalmoscopy, in the diagnosis of ocular melanoma. This is because ultrasound allows eye specialists to view structures that cannot otherwise be assessed. Ultrasonography also produces highquality images that allow the ophthalmologist or ocular oncologist to measure the size, shape, and extent of tumors. Ultrasound is a quick and convenient means of obtaining excellent images of the posterior segment when there is a cloudy cornea, dense cataract, or vitreous hemorrhage. Adequate training, however, is essential to reap the benefits ultrasound can offer in the diagnosis and treatment of uveal melanoma.

Bertil Damato, MD, PhD, FRCOphth, is Director of Ocular Oncology Service and Professor of Ophthalmology and Radiation Oncology at the University of California, San Francisco, Medical Center. He may be reached at +1 415 514-6918; or at DamatoB@Vision.UCSF.edu.

Kelly Babic, MSc, CDOS, COA, is an Ophthalmic Ultrasonographer and the Diagnostic Services/Clinic Manager at University of California, San Francisco, Medical Center. She may be reached at Kelly.Babic@UCSFmedctr.org.

  1. Ocular Melanoma Foundation. About ocular melanoma. http://www.ocularmelanoma. org/about-om.htm. Accessed October 22, 2013.
  2. Melanoma Research Foundation. Diagnosing ocular melanoma. http://www.melanoma. org/understand-melanoma/what-is-melanoma/ocular-melanoma/diagnosing-ocularmelanoma. Accessed October 22, 2013.
  3. Kivelä T. Diagnosis of uveal melanoma. Dev Ophthalmol. 2012; 49:1-15.
  4. Damato B. Progress in the management of patients with uveal melanoma. The 2012 Ashton Lecture. Eye. 2012;26:1157-1172.
  5. Byrne S, Green RL. Ultrasound of the Eye and Orbit, 2nd Edition. Philadelphia: Mosby; 2002. 145-190.
  6. Ellex Eye Cubed Brochure. http://www.ellex.com/corp/products/diagnostic-ultrasound/ eye-cubed. Accessed October 22, 2013.