Radiology
HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
QUICK SEARCH:   [advanced]


     

This Article
Right arrow Abstract Freely available
Right arrow Figures Only
Right arrow Full Text (PDF)
Right arrow Submit a response
Right arrow Alert me when this article is cited
Right arrow Alert me when eLetters are posted
Right arrow Alert me if a correction is posted
Right arrow Citation Map
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrow reprints & permissions
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Lemke, A.-J.
Right arrow Articles by Felix, R.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Lemke, A.-J.
Right arrow Articles by Felix, R.
(Radiology. 1999;210:775-783.)
© RSNA, 1999

Head and Neck Imaging

Uveal Melanoma: Correlation of Histopathologic and Radiologic Findings by Using Thin-Section MR Imaging with a Surface Coil

Arne-Jörn Lemke, MD1, Norbert Hosten, MD1, Norbert Bornfeld, MD2, Nikolaos E. Bechrakis, MD3, Andreas Schüler, MD2, Miriam Richter, MD1, Christian Stroszczynski, MD1 and Roland Felix, MD1

1 Universitätsklinikum Charité, Campus Virchow-Klinikum, Medizinische Fakultät der Humboldt Universität zu Berlin, Strahlenklinik und Poliklinik, Augustenburger Platz 1, D-13353 Berlin, Germany (A.J.L., N.H., M.R., C.S., R.F.)
2 Universität-Gesamthochschule Essen, Augenklinik (N.B., A.S.)
3 Klinikum Benjamin-Franklin, Augenklinik und Poliklinik, (N.E.B.).


   Abstract
TOP
 Abstract
Introduction
 MATERIALS AND METHODS
 RESULTS
 DISCUSSION
 References
 
PURPOSE: To evaluate whether the different signal intensities at magnetic resonance (MR) imaging of melanoma are associated with a higher content of melanin.

MATERIALS AND METHODS: In a prospective study, MR imaging and ophthalmoscopic examination findings in 42 patients (19 women, 23 men; age range, 30–87 years) with uveal melanoma were compared with histopathologic examination findings obtained after enucleation. MR imaging was performed with 2-mm sections by using a 5-cm surface coil. T1- and T2-weighted images were obtained before and after contrast material administration.

RESULTS: In 33 (79%) of the patients, there was homogeneous tumor pigmentation, whereas in nine (21%) patients, there was inhomogeneous bipartite tumor pigmentation. Compared with the histopathologic data, the results of qualitative evaluation were accurate in 29 (58%) of 50 and in 26 (53%) of 49 tumorous areas on T1- and T2-weighted images, respectively. Quantitative evaluation yielded better results, especially at T1-weighted imaging; an 86% correlation was found. Because of methodological reasons, only the superficial pigmentation of inhomogeneous tumors could be evaluated with ophthalmoscopy.

CONCLUSION: Thin-section MR imaging of the eye enables an accurate prediction of melanomatous pigmentation with quantitative evaluation of plain T1-weighted images and is superior to ophthalmoscopy in cases of inhomogeneous pigmentation.

Index terms: Eye, MR, 224.12143, 224.12146 • Eye, neoplasms, 224.371 • Magnetic resonance (MR), surface coils, 224.12143, 224.12146 • Magnetic resonance (MR), tissue characterization, 224.12143, 224.12146 • Melanoma, 224.371


   Introduction
TOP
 Abstract
 Introduction
MATERIALS AND METHODS
 RESULTS
 DISCUSSION
 References
 
Malignant melanoma of the uvea is the most common form of intraocular malignancy (1,2); it occurs in five to seven of every 1,000,000 people (1–4). Seventy percent of malignant intraocular tumors are melanomas, followed by metastatic carcinoma and retinoblastoma in the pediatric population, each of which composes about 10% of carcinomas in this patient group (4). Among uveal melanomas there are, in order of decreasing frequency, choroidal melanomas, ciliary body melanomas, and iris melanomas (5,6).

In recent years, the spatial resolution in ocular magnetic resonance (MR) imaging has improved considerably as a result of advances in medical technology. MR imaging can now contribute to the staging and possibly to the differential diagnosis of uveal melanoma (7). In particular, tumor staging and other prognostic factors help to determine the therapeutic procedure.

An important prognostic factor is the degree of tumor pigmentation, because more pronounced pigmentation indicates a less favorable prognosis (5,8,9). In addition, the prognosis worsens with increasing tumor size, extraocular growth, and infiltration of the ciliary body (5,8,9). Retinal detachment, which is associated with uveal melanoma, is regarded as a sign of progressive tumor development because, according to the literature (10), it appears "in the late stages of tumor growth," that is, with progressive tumor growth, which is characterized by large volume, extraocular growth, and a destroyed Bruch membrane. However, the development of retinal detachment depends on individual factors also; thus, small melanomas can have retinal detachment. Equally important for staging before therapy are the size, shape, and location of the tumor.

MR imaging allows the investigator to examine the eye independently in all spatial dimensions and to reproduce the results (11–15). The insufficient spatial resolution that has been cited as a disadvantage of MR imaging can be offset with the use of special surface coils (16–19).

In a small series (20), a linear relation between the MR imaging signal intensity and the melanin content in uveal melanoma was revealed. The purpose of this study was to evaluate, on the basis of histopathologic examination results in patients with uveal melanoma, whether different MR imaging signal intensities are caused by variations in melanin content and whether MR imaging can enable the prediction of the pigmentation degree before therapy. The results were compared with the ophthalmoscopic findings obtained before enucleation.


   MATERIALS AND METHODS
TOP
 Abstract
 Introduction
 MATERIALS AND METHODS
RESULTS
 DISCUSSION
 References
 
In a prospective study, 42 patients (19 women, 23 men; age range, 30–87 years; median age, 62 years) with histopathologically proved intraocular melanoma that was treated by using enucleation were examined. Thin-section MR imaging of the respective eye and ophthalmoscopy were performed in all patients before surgery. The study was approved by the local ethics committee, and all patients provided written informed consent. To exclude the possibility of another primary tumor, imaging of the chest, ultrasonography (US) of the liver, and a detailed physical examination were performed. None of the patients had other melanomas in other parts of the body at the time of the physical examination or at surgery. We thus concluded that all of the tumors in our study were primary intraocular melanomas.

MR images were obtained on a 1.5-T superconducting system (Magnetom SP63; Siemens Medical Systems, Erlangen, Germany) by using a special 5-cm surface coil. This coil, which was constructed to meet the special needs of orbital imaging and to protect the patient from local heating, is equipped with a nonmagnetic fuse (18,21). The local ethics committee approved our use of the surface coil in orbital examinations. The patients then signed a patient consent form after being informed of the risks involved in MR imaging and of the special risks associated with the use of surface coils. To reduce motion artifacts, the patient's head was immobilized by placing rice bags on the side of the head, and the coil was attached about 1 cm above the respective eye. First, T2-weighted (n = 25) or fast T2-weighted (n = 17) and T1-weighted (n = 42) images were obtained in a transverse direction. After the intravenous administration of 0.1 mmol of Magnevist (Schering, Berlin, Germany) per kilogram of body weight, transverse T1-weighted images as well as T1-weighted images in an additional plane were obtained, depending on the relative position of the melanoma. The following parameters were used to obtain T1-weighted images: 600/20 (repetition time msec/echo time msec); two acquisitions; bandwidth, 78 Hz; field of view, 60 mm; matrix, 256 x 256; and duration, 5 minutes, 10 seconds. The following parameters were used to obtain T2-weighted images: 2,300/90 and 15, respectively; one acquisition; bandwidth, 65 Hz; field of view, 90 mm; matrix, 240 x 256; and duration, 9 minutes, 16 seconds. The following parameters were used to obtain fast T2-weighted images: 4,600/90, two acquisitions, bandwidth, 78 Hz; field of view, 90 mm; matrix, 240 x 256; and duration, 6 minutes, 19 seconds.

The signal intensity and contrast of the tumors and retinal detachments were evaluated qualitatively and quantitatively on T1- and T2-weighted images obtained before contrast material administration. In a qualitative evaluation, the signal intensity of the melanoma was compared with the signal intensity of the vitreous body. The retinal detachments were evaluated similarly. The vitreous body was chosen as a reference medium for two reasons. First, it is the only structure in the eye with a chemical composition that remains constant unless it is affected by disturbing factors such as bleeding or diffuse vitreous hyperintensity, which rarely occur. Diffuse vitreous hyperintensity is described in the literature (22,23) as an increase in the signal intensity of the vitreous body compared with the signal intensity of the contralateral vitreous body. This increase in signal intensity may be due to discrete vitritis or damage to the blood-retinal barrier, with leakage of protein. Second, the use of the vitreous body as a reference medium guarantees the comparability with other studies (24).

The following classification of signal intensity was used: +2, hyperintense; +1, moderately hyperintense; 0, isointense; -1, moderately hypointense; and -2, hypointense. Various values were determined when clear differences in the signal intensities within the tumor were observed. On the basis of our study results and data from the literature, we tried to draw conclusions about the melanin content of tumors based on the signal intensities within the tumors.

For the quantitative evaluation, the signal intensities within the tumor, retinal detachment, and vitreous body were measured within a region of interest of constant size with all of the sequences used by copying the region of interest from one sequence to another. Manual correction was performed in only those cases where the patient's head had moved between two measurements. In cases of inhomogeneous tumor pigmentation, several values were measured. Accordingly, further parameters, such as the ratio of melanomatous signal intensity to vitreous body signal intensity, were calculated. We used this ratio to determine the tumorous regions in amelanotic (ratio < 1.5), moderately pigmented (ratio 1.5–2.0), and strongly pigmented (ratio > 2.0) tumors observed on the T1-weighted images. Consequently, for the T2-weighted images, the limits were set at 0.5, which was the lower limit for amelanotic melanoma, and 0.4, which was the lower limit for more strongly pigmented melanoma. These results were compared with the histopathologic findings.

The size, shape, and position of the tumor in the eye as well as the presence of retinal detachment were important for the evaluation. Each melanoma was categorized into one of three groups according to its size and shape. We differentiated between small melanomas, which had a volume below 0.5 mL, medium-sized melanomas with a volume between 0.5 and 1.0 mL, and large melanomas, which had a volume above 1.0 mL. The volume was calculated on the basis of three representative diameters according to the following equation: volume = a x b x c/2, where a is the tumor prominence, that is, the maximum distance from the tumor base to the tumor surface rectangular to the base; b, the largest tumor diameter in a transverse plane parallel to the tumor base; and c, the number of sections with visible tumor multiplied by the section thickness. The extent of retinal detachment was estimated in the same way. Calculating the volume with this formula provides only an estimation of the volume, and it is necessary to imagine an ellipsoid or spheric shape of the tumor and retinal detachment, which then approximately represents the mass. The tumor shapes were flat, mound-shaped, and mushroom-shaped, with a wide base and ruptured Bruch membrane. The ruptured Bruch membrane is not directly visible as the layer between the retina and the uvea with MR imaging, but the mushroom shape is an indication of the rupture and a sign of progressive tumor development. For the prognostically relevant classification of tumor positions, we differentiated between melanomas with the main part posterior to the equator and those with the main part anterior to the equator. The latter mentioned tumors were, in addition, divided into melanomas that were infiltrating the ciliary body and those that were not. Analogously, the ophthalmoscopically visible pigmentation of the tumors before surgery was graded as follows: 2, strongly pigmented; 1, moderately pigmented; and 0, amelanotic.

After enucleation, the eyes were fixed in 4% formaldehyde and bisected along the plane of the MR imaging orientation. Five-micron-thick sections were stained with hematoxylin-eosin and with periodic acid–Schiff stain. Histopathologically evaluated pigmentation of the melanomas was classified as previously described. In cases of inhomogeneous pigmentation, various values were obtained.


   RESULTS
TOP
 Abstract
 Introduction
 MATERIALS AND METHODS
 RESULTS
DISCUSSION
 References
 
In all 42 patients, the melanoma could be differentiated from the retinal detachment. Shape, position, and, in particular, contrast enhancement helped to differentiate tumor from retinal detachment. The signal intensities in retinal detachments remained unchanged after contrast material administration.

Small melanomas—that is, those with a volume less than 0.5 mL—were found in 13 (31%); medium-sized melanomas with a volume between 0.5 and 1.0 mL, in 14 (33%); and large melanomas—that is, those with a volume greater than 1.0 mL—in 15 (36%) patients. The average tumor size was 0.93 mL (size range, 0.02–2.58 mL). The mushroom-shaped tumors were found most frequently, in 21 (50%) patients, followed by the mound-shaped tumors, which were found in 13 (31%) patients, and the flat tumors, which were found in eight (19%) patients. In 26 (62%) patients, the main portion of the melanoma was located in the posterior part of the eye, whereas in 16 (38%) patients, it was found in the anterior part, which is not easily accessible by using ophthalmoscopy. In nine (21%) patients, the melanomas were infiltrating the ciliary body. Twenty-six (62%) patients had histopathologically proved scleral infiltration, none of which was detectable by using MR imaging. However, in seven of eight patients with histopathologically proved extraocular growth, a diagnosis could be made by using MR imaging. In two cases, optic nerve infiltration was observed at both MR imaging and histopathologic examination. No cases of optic nerve infiltration were overlooked at MR imaging.

In 39 (93%) patients, retinal detachment was detected in the vicinity of the tumor with MR imaging. Only three patients with small tumors showed no retinal detachment. The volumes of subretinal fluid or blood varied considerably, with a volume range of 0.03–3.75 mL and a mean volume of 0.68 mL with total detachment. No relation between the extent of detachment and the tumor size was observed. Small melanomas had large retinal detachments; the limiting factor in large melanomas was the volume of the eye.

In 33 (79%) patients, the MR imaging signal intensities of the melanomas were homogeneous. Thus, we concluded that the tumor pigmentation was homogeneous. In nine (21%) patients, there were different signal intensities within the melanomas; this represented mixed pigmentation (Fig 1). In the histologic sections, the distribution of pigmentation, as classified on MR images, could be confirmed in all cases. Hence, we decided to evaluate the 51 different tumorous areas (ie, 33 homogeneous melanomas plus two tumorous areas in each of the nine inhomogeneous tumors) separately. Of the 51 different tumorous areas, 23 (45%) were classified as strongly pigmented; 17 (33%), as little or moderately pigmented; and 11 (22%), as amelanotic. Qualitative (ie, visual) MR imaging (Table 1) enabled the accurate prediction of the level of pigmentation at histopathologic examination in 29 (58%) of 50 areas on T1-weighted images and in 26 (53%) of 49 areas on T2-weighted images (Figs 2–4).



View larger version (157K):
[in this window]
[in a new window]
  		Figure 1a. Inhomogeneous pigmented uveal melanoma of the right eye in a 30-year-old patient. In a–d, ant. = anterior direction, C = ciliary body, cran. = cranial direction, D = retinal detachment, L = lens, nas. = nasal direction, R = retina, S = sclera, temp. = temporal direction, V = vitreous body. (a) Axial T1-weighted MR image (600/20, 256 x 256 matrix, two acquisitions) shows different signal intensities within the melanoma (M), with higher signal intensities in the ventral and medial parts of the tumor (arrows) than in the main part. (b) Axial T2-weighted image (2,300/90, 240 x 256 matrix, one acquisition) shows hypointensities in the ventral and medial parts of the melanoma, which correspond to the higher signal intensities in a. (c) Ophthalmoscopic image shows a poorly defined tumor (M) at the temporal edge of the field of view. The tumor is poorly defined because of its anterior position. A normal optic disk (O) also is seen. (d) Histologic preparation (hematoxylin-eosin stain; original magnification, x200) of an axial section shows an increased concentration of melanin (arrows) in a small band ventrally.

 


View larger version (141K):
[in this window]
[in a new window]
  		Figure 1b. Inhomogeneous pigmented uveal melanoma of the right eye in a 30-year-old patient. In a–d, ant. = anterior direction, C = ciliary body, cran. = cranial direction, D = retinal detachment, L = lens, nas. = nasal direction, R = retina, S = sclera, temp. = temporal direction, V = vitreous body. (a) Axial T1-weighted MR image (600/20, 256 x 256 matrix, two acquisitions) shows different signal intensities within the melanoma (M), with higher signal intensities in the ventral and medial parts of the tumor (arrows) than in the main part. (b) Axial T2-weighted image (2,300/90, 240 x 256 matrix, one acquisition) shows hypointensities in the ventral and medial parts of the melanoma, which correspond to the higher signal intensities in a. (c) Ophthalmoscopic image shows a poorly defined tumor (M) at the temporal edge of the field of view. The tumor is poorly defined because of its anterior position. A normal optic disk (O) also is seen. (d) Histologic preparation (hematoxylin-eosin stain; original magnification, x200) of an axial section shows an increased concentration of melanin (arrows) in a small band ventrally.

 


View larger version (94K):
[in this window]
[in a new window]
  		Figure 1c. Inhomogeneous pigmented uveal melanoma of the right eye in a 30-year-old patient. In a–d, ant. = anterior direction, C = ciliary body, cran. = cranial direction, D = retinal detachment, L = lens, nas. = nasal direction, R = retina, S = sclera, temp. = temporal direction, V = vitreous body. (a) Axial T1-weighted MR image (600/20, 256 x 256 matrix, two acquisitions) shows different signal intensities within the melanoma (M), with higher signal intensities in the ventral and medial parts of the tumor (arrows) than in the main part. (b) Axial T2-weighted image (2,300/90, 240 x 256 matrix, one acquisition) shows hypointensities in the ventral and medial parts of the melanoma, which correspond to the higher signal intensities in a. (c) Ophthalmoscopic image shows a poorly defined tumor (M) at the temporal edge of the field of view. The tumor is poorly defined because of its anterior position. A normal optic disk (O) also is seen. (d) Histologic preparation (hematoxylin-eosin stain; original magnification, x200) of an axial section shows an increased concentration of melanin (arrows) in a small band ventrally.

 


View larger version (105K):
[in this window]
[in a new window]
  		Figure 1d. Inhomogeneous pigmented uveal melanoma of the right eye in a 30-year-old patient. In a–d, ant. = anterior direction, C = ciliary body, cran. = cranial direction, D = retinal detachment, L = lens, nas. = nasal direction, R = retina, S = sclera, temp. = temporal direction, V = vitreous body. (a) Axial T1-weighted MR image (600/20, 256 x 256 matrix, two acquisitions) shows different signal intensities within the melanoma (M), with higher signal intensities in the ventral and medial parts of the tumor (arrows) than in the main part. (b) Axial T2-weighted image (2,300/90, 240 x 256 matrix, one acquisition) shows hypointensities in the ventral and medial parts of the melanoma, which correspond to the higher signal intensities in a. (c) Ophthalmoscopic image shows a poorly defined tumor (M) at the temporal edge of the field of view. The tumor is poorly defined because of its anterior position. A normal optic disk (O) also is seen. (d) Histologic preparation (hematoxylin-eosin stain; original magnification, x200) of an axial section shows an increased concentration of melanin (arrows) in a small band ventrally.

 

View this table:
[in this window]
[in a new window]
  		TABLE 1. Qualitative Evaluation of Pigmentation with MR Imaging versus with Histopathologic Analysis
 


View larger version (175K):
[in this window]
[in a new window]
  		Figure 2a. Strongly pigmented choroidal melanoma of the right eye in a 62-year-old patient. In a–d, ant. = anterior direction, cran. = cranial direction, L = lens, nas. = nasal direction, temp. = temporal direction, V = vitreous body. (a) Axial T1-weighted image (600/20, 256 x 256 matrix, two acquisitions) shows a strongly hyperintense tumor (M). The retinal detachment (D) is clearly hypointense compared with the tumor but hyperintense compared with the vitreous body. (b) Axial T2-weighted image (2,300/90, 240 x 256 matrix, one acquisition) shows a strongly hypointense tumor (M). The retinal detachment (D) is nearly isointense compared with the vitreous body (V). (c) Ophthalmoscopic image shows very dark tumor (M) in the center of the image, with extended retinal detachment (D). A small part of the normal retina-choroid in the temporal-cranial direction is visible. (d) Histopathologic preparation (hematoxylin-eosin stain; original magnification, x200) of an axial section shows the tumor base (M) adjacent to the nasal sclera (S), with more pronounced pigmentation. The retinal detachment is not visible because of the preparation method.

 


View larger version (148K):
[in this window]
[in a new window]
  		Figure 2b. Strongly pigmented choroidal melanoma of the right eye in a 62-year-old patient. In a–d, ant. = anterior direction, cran. = cranial direction, L = lens, nas. = nasal direction, temp. = temporal direction, V = vitreous body. (a) Axial T1-weighted image (600/20, 256 x 256 matrix, two acquisitions) shows a strongly hyperintense tumor (M). The retinal detachment (D) is clearly hypointense compared with the tumor but hyperintense compared with the vitreous body. (b) Axial T2-weighted image (2,300/90, 240 x 256 matrix, one acquisition) shows a strongly hypointense tumor (M). The retinal detachment (D) is nearly isointense compared with the vitreous body (V). (c) Ophthalmoscopic image shows very dark tumor (M) in the center of the image, with extended retinal detachment (D). A small part of the normal retina-choroid in the temporal-cranial direction is visible. (d) Histopathologic preparation (hematoxylin-eosin stain; original magnification, x200) of an axial section shows the tumor base (M) adjacent to the nasal sclera (S), with more pronounced pigmentation. The retinal detachment is not visible because of the preparation method.

 


View larger version (101K):
[in this window]
[in a new window]
  		Figure 2c. Strongly pigmented choroidal melanoma of the right eye in a 62-year-old patient. In a–d, ant. = anterior direction, cran. = cranial direction, L = lens, nas. = nasal direction, temp. = temporal direction, V = vitreous body. (a) Axial T1-weighted image (600/20, 256 x 256 matrix, two acquisitions) shows a strongly hyperintense tumor (M). The retinal detachment (D) is clearly hypointense compared with the tumor but hyperintense compared with the vitreous body. (b) Axial T2-weighted image (2,300/90, 240 x 256 matrix, one acquisition) shows a strongly hypointense tumor (M). The retinal detachment (D) is nearly isointense compared with the vitreous body (V). (c) Ophthalmoscopic image shows very dark tumor (M) in the center of the image, with extended retinal detachment (D). A small part of the normal retina-choroid in the temporal-cranial direction is visible. (d) Histopathologic preparation (hematoxylin-eosin stain; original magnification, x200) of an axial section shows the tumor base (M) adjacent to the nasal sclera (S), with more pronounced pigmentation. The retinal detachment is not visible because of the preparation method.

 


View larger version (123K):
[in this window]
[in a new window]
  		Figure 2d. Strongly pigmented choroidal melanoma of the right eye in a 62-year-old patient. In a–d, ant. = anterior direction, cran. = cranial direction, L = lens, nas. = nasal direction, temp. = temporal direction, V = vitreous body. (a) Axial T1-weighted image (600/20, 256 x 256 matrix, two acquisitions) shows a strongly hyperintense tumor (M). The retinal detachment (D) is clearly hypointense compared with the tumor but hyperintense compared with the vitreous body. (b) Axial T2-weighted image (2,300/90, 240 x 256 matrix, one acquisition) shows a strongly hypointense tumor (M). The retinal detachment (D) is nearly isointense compared with the vitreous body (V). (c) Ophthalmoscopic image shows very dark tumor (M) in the center of the image, with extended retinal detachment (D). A small part of the normal retina-choroid in the temporal-cranial direction is visible. (d) Histopathologic preparation (hematoxylin-eosin stain; original magnification, x200) of an axial section shows the tumor base (M) adjacent to the nasal sclera (S), with more pronounced pigmentation. The retinal detachment is not visible because of the preparation method.

 


View larger version (153K):
[in this window]
[in a new window]
  		Figure 4a. Amelanotic melanoma of the right eye in a 72-year-old patient. In a–d, ant. = anterior direction, cran. = cranial direction, L = lens, nas. = nasal direction, R = retina, S = sclera, temp. = temporal direction, V = vitreous body. (a) Axial T1-weighted MR image (600/20, 256 x 256 matrix, two acquisitions) shows the signal intensity of the tumor (M) to be nearly isointense to that of the vitreous body (V). The retinal detachment (D) has a distinctly higher signal intensity. (b) Axial T2-weighted image (2,300/90, 240 x 256 matrix, one acquisition) shows the tumor (M) to be hypointense compared with the vitreous body (V). The retinal detachment (D) is almost isointense to the melanoma (M). (c) Ophthalmoscopic image shows a light melanoma (M) near the temporal edge of the field of view, with an overlying bloody retinal detachment (D) masking the tumor up to the optic disk (O). (d) Histopathologic preparation (hematoxylin-eosin stain; original magnification, x200) of an axial section shows the amelanotic tumor (M) reaching the optic disk (O).

 


View larger version (134K):
[in this window]
[in a new window]
  		Figure 4b. Amelanotic melanoma of the right eye in a 72-year-old patient. In a–d, ant. = anterior direction, cran. = cranial direction, L = lens, nas. = nasal direction, R = retina, S = sclera, temp. = temporal direction, V = vitreous body. (a) Axial T1-weighted MR image (600/20, 256 x 256 matrix, two acquisitions) shows the signal intensity of the tumor (M) to be nearly isointense to that of the vitreous body (V). The retinal detachment (D) has a distinctly higher signal intensity. (b) Axial T2-weighted image (2,300/90, 240 x 256 matrix, one acquisition) shows the tumor (M) to be hypointense compared with the vitreous body (V). The retinal detachment (D) is almost isointense to the melanoma (M). (c) Ophthalmoscopic image shows a light melanoma (M) near the temporal edge of the field of view, with an overlying bloody retinal detachment (D) masking the tumor up to the optic disk (O). (d) Histopathologic preparation (hematoxylin-eosin stain; original magnification, x200) of an axial section shows the amelanotic tumor (M) reaching the optic disk (O).

 


View larger version (108K):
[in this window]
[in a new window]
  		Figure 4c. Amelanotic melanoma of the right eye in a 72-year-old patient. In a–d, ant. = anterior direction, cran. = cranial direction, L = lens, nas. = nasal direction, R = retina, S = sclera, temp. = temporal direction, V = vitreous body. (a) Axial T1-weighted MR image (600/20, 256 x 256 matrix, two acquisitions) shows the signal intensity of the tumor (M) to be nearly isointense to that of the vitreous body (V). The retinal detachment (D) has a distinctly higher signal intensity. (b) Axial T2-weighted image (2,300/90, 240 x 256 matrix, one acquisition) shows the tumor (M) to be hypointense compared with the vitreous body (V). The retinal detachment (D) is almost isointense to the melanoma (M). (c) Ophthalmoscopic image shows a light melanoma (M) near the temporal edge of the field of view, with an overlying bloody retinal detachment (D) masking the tumor up to the optic disk (O). (d) Histopathologic preparation (hematoxylin-eosin stain; original magnification, x200) of an axial section shows the amelanotic tumor (M) reaching the optic disk (O).

 


View larger version (122K):
[in this window]
[in a new window]
  		Figure 4d. Amelanotic melanoma of the right eye in a 72-year-old patient. In a–d, ant. = anterior direction, cran. = cranial direction, L = lens, nas. = nasal direction, R = retina, S = sclera, temp. = temporal direction, V = vitreous body. (a) Axial T1-weighted MR image (600/20, 256 x 256 matrix, two acquisitions) shows the signal intensity of the tumor (M) to be nearly isointense to that of the vitreous body (V). The retinal detachment (D) has a distinctly higher signal intensity. (b) Axial T2-weighted image (2,300/90, 240 x 256 matrix, one acquisition) shows the tumor (M) to be hypointense compared with the vitreous body (V). The retinal detachment (D) is almost isointense to the melanoma (M). (c) Ophthalmoscopic image shows a light melanoma (M) near the temporal edge of the field of view, with an overlying bloody retinal detachment (D) masking the tumor up to the optic disk (O). (d) Histopathologic preparation (hematoxylin-eosin stain; original magnification, x200) of an axial section shows the amelanotic tumor (M) reaching the optic disk (O).

 
The results of quantitative evaluation showed a higher correlation between the relative signal intensities and the histopathologically proved pigmentation. On the T1-weighted images, the signal intensities of the tumor relative to the vitreous body were higher with increasing pigmentation. On the T2-weighted images, the relative signal intensity decreased. In the quantitative evaluation, the ratio of the melanomatous signal intensity to the vitreous body signal intensity was a reliable parameter for tumor pigmentation. By using these criteria, the melanin content on the T1-weighted images was accurately determined in 43 (86%) of 50 tumorous areas (Table 2). The pigmentation of tumors in three patients with amelanotic and in four patients with moderately pigmented tumorous areas was overestimated by using MR imaging; underestimation of pigmentation did not occur. The average ratio of the histopathologically proved amelanotic tumorous areas was 1.43; of the moderately pigmented tumorous areas, 1.87; and of the strongly pigmented areas, 2.71. The correlation between T2-weighted imaging findings and histopathologic data was, however, low; the findings correlated in 12 (26%) of 46 areas.


View this table:
[in this window]
[in a new window]
  		TABLE 2. Quantitative Evaluation of Pigmentation with MR Imaging versus with Histopathologic Analysis
 
In five (12%) of 42 patients, the degree of pigmentation could not be detected at ophthalmoscopic examination because of opaque media (ie, fluid from retinal detachment and extensive bleeding) blocking the view. In an additional nine (21%) patients with inhomogeneous pigmentation, the degree of pigmentation in only the small ventral part of the tumor could be estimated; this was not representative of the overall pigmentation in the tumor. In 28 (67%) patients, an exact assessment of the degree of pigmentation was performed by comparing the ophthalmoscopic findings with the histopathologic findings.


   DISCUSSION
TOP
 Abstract
 Introduction
 MATERIALS AND METHODS
 RESULTS
 DISCUSSION
References
 
MR imaging is an adequate diagnostic tool for tumor staging and for evaluating prognostically important diagnostic details. For a differential diagnosis of intraocular tumors, however, MR imaging is less useful, because in most cases the diagnosis has already been established with ophthalmoscopy, fluorescence angiography, or US. In recent years, several factors were found to be of prognostic importance for the assessment of uveal melanoma. The prognosis was less favorable when increasing tumor size, extraocular growth, or infiltration of the ciliary body was observed (5,8,9). Another prognostic factor is the degree of pigmentation in the tumor, with stronger pigmentation being indicative of a less favorable prognosis (5,8,9). Hence, individual therapy depends on prognosis as well as on other factors. If the visual function can be preserved, local globe maintenance therapies such as local excision, brachytherapy with iodine or ruthenium applicators, or percutaneous irradiation with protons or helium particles are given preference over more radical therapies such as enucleation or exenteration. On the other hand, with a confirmed poorer prognosis, a more aggressive treatment must be considered, but a very poor prognosis with regard to survival might not justify radical treatment (25–30).

In early works in MR imaging, the paramagnetic effects of melanin were described. Systematic evaluation of the effects of melanin on signal intensity encountered with different pulse sequences was not possible, however. This was owing to the insufficient spatial resolution of the scanners that were available then. Shortening of the T1 and T2 relaxation times induces increased signal intensities on T1-weighted images and decreased signal intensities on T2-weighted images (24,31). Among eye tumors, only melanomas exhibit this signal intensity behavior, which is used as the main diagnostic criterion to differentiate eye tumors (32). One group (20) observed a linear correlation between signal intensity and melanin content and pointed out the prognostic value of the T2 relaxation time. However, single cases of characteristic signs of melanoma that at histopathologic examination proved to be metastases with other histopathologic features have been reported (33,34). These discordant findings may be explained with the qualitative evaluation in the mentioned studies, but they should be grounds for caution when establishing a differential diagnosis, because there is a gray zone between melanoma and metastases. On the other hand, there are melanomas that do not fulfill the typical criteria because of their low melanin content or lack of melanin.

In several studies (32,35–37) with larger numbers of patients, single cases of amelanotic melanoma have been reported. In our series, eight amelanotic and three partially amelanotic melanomas were found histopathologically. Compared with the signal intensity of the vitreous body, the signal intensity of 10 of these tumors was slightly hyperintense or isointense on T1-weighted images and slightly hypointense on T2-weighted images. This is similar to the signal intensities of choroidal metastases and of other tumors of the eye (33,34). The 25 melanotic melanomas and the melanotic parts of the nine melanomas with mixed pigmentation almost always had a high signal intensity on T1-weighted images and a very low signal intensity on T2-weighted images. Nevertheless, a reliable visual evaluation of the pigmentation in the tumorous areas was possible in only 57% and 51% of tumorous areas on T1- and T2-weighted images, respectively.

The determination of the signal intensity of the tumor in relation to that of the vitreous body seemed to be difficult. Errors can occur for several reasons: (a) Because signal intensity decreases with increasing distance from the surface coil, an accurate evaluation is possible only if the distances from the examined structures to the coil are the same. Visually, this condition is difficult to establish. (b) Motion artifacts can falsify signal intensities within both the tumor and the vitreous body and thereby result in a high SD of the mean values. (c) Depending on the tumor size and signal intensities of the surrounding entities (eg, blood, serous retinal detachment, vitreous body, or orbital fat), misinterpretation of signal intensities can result from the different contrasts of these materials. Finally, falsification can result from unsuitable window settings.

The quantitative evaluation of the signal intensities within the tumor in relation to those in the vitreous body proved to be more reliable than the visual evaluation of the melanin content before surgery; the correlation was about 86%. Evaluation of the relative signal intensities can be performed regardless of the chosen window level and therefore does not depend on the investigator either. The results of former studies indicated that with surface coils, a marked change in the signal intensity within a homogeneous medium can be achieved by increasing the distance from the coil and thereby decreasing the signal intensities. Because different investigators can obtain different results, the determined regions of interest must be the same distance from the coil and must be located in an area that does not have artifacts. If these conditions are established, reliable values can be expected. According to the results of our study, T1-weighted images are best for the prediction of pigmentation, the upper margin for amelanotic melanoma is a ratio of 1.5, and the lower margin for strongly pigmented melanoma is a ratio of 2.0. The low correlation between T2-weighted imaging findings and pigmentation (26%) has been observed with cutaneous melanoma also (38) and is owing to the lower spatial resolution and greater number of motion artifacts on T2-weighted images compared with T1-weighted images.

One advantage of MR imaging over ophthalmoscopy that, to our knowledge, has not been mentioned in the literature to date is that it enables assessment of the distribution of pigmentation within the whole melanoma. By using ophthalmoscopy, only the ventral part of the tumor can be evaluated. In our study, 21% of the patients had inhomogeneous pigmentation, which in all cases was considered to be higher at ophthalmoscopy. This was because the pigmentation was more pronounced in the small anterior rather than in the main part of the tumor, that is, it was invisible at ophthalmoscopy. The area of strongest pigmentation and the prognosis with these mixed melanomas can be accurately determined with ophthalmoscopy; however, if the pigmentation is more pronounced in the center of the tumor, it will be underestimated with ophthalmoscopy, and the subsequent prognosis will be too optimistic. This is a potential source of error with ophthalmoscopy and an additional indication for MR imaging. With regard to the quantitative evaluation of melanomatous pigmentation, the accuracy in determining the pigmentation level can be improved from 67% by using ophthalmoscopy to 86%.

The size, shape, and position of the tumor are of great importance for therapy-related decisions. Brachytherapy with radioactive plaques is possible with small and medium-sized tumors up to 8–9 mm (30) if visual ability can be preserved. In this study, enucleated eyes were available to facilitate understanding of MR imaging in melanoma delineation. However, one limitation of our study design was that the average tumor size was larger than the tumor size expected to be seen in a tertiary referral center. This was because the sample was limited to patients who had undergone enucleation. According to our experience with more than 200 uveal melanomas, the average volume of these melanomas, 0.93 mL, is larger than the average volume of consecutive melanomas at the time of recognition (0.61 mL). In particular, extensive findings of volumes greater than 2 mL, which were seen in four cases in this study, are rare.

Tumors in a prognostically unfavorable position—that is, ventral from the equator—with infiltration of the ciliary body, as well as tumors near the optic nerve and those with a prominence of more than 10 mm are more prevalent than expected. With regard to tumor dimensions and volumes, a high correlation with histopathologic results was observed. Tumor shapes also are of prognostic and therapeutic importance. The mushroom shape is a sign of progressive and infiltrative tumor development, which necessitates a more aggressive therapy, whereas the mound-shaped tumors have a more displacing growth. The flat tumors are ambiguous; they either show infiltrative tumor development with extraocular growth or remain small over several years of observation. As described recently, MR imaging has a sensitivity of 86% and a specificity of 71% in the detection of extraocular growth. Compared with US, which has a sensitivity of 43% and a specificity of 37%, MR imaging with surface coils is superior and has better interobserver reliability (39). Optic nerve infiltration can be visualized reliably; however, microscopic infiltration of the sclera without extraocular growth is not detectable at MR imaging but rather at histopathologic examination only.

Most eye tumors are accompanied by retinal detachment. The values given in the literature differ, depending on the tumor type and investigative method. In metastases, a prevalence of 72% was found (34); in melanoma, a retinal detachment was seen in "some" patients (40). Generally, retinal detachment associated with melanoma is regarded as a sign of progressive tumor development (10). A criterion for retinal detachment is the morphologically typical V shape, with the retina divided into two parts as a result of its attachment within the region of the optic nerve disk and the pars plana of the ciliary body (10). Successful differentiation of retinal detachment or subretinal bleeding from solid tumors can be achieved by means of contrast material administration (32,41). In our series, MR imaging demonstrated retinal detachment in 39 (93%) patients. In a study of more than 200 consecutive uveal melanomas, we found a lower prevalence (in 65% of the cases) of retinal detachment. This was owing primarily to the more progressive tumor growth in the patients that were treated with enucleation in the present study. Contrast material enhancement made differentiation between the tumor and retinal detachment possible in all cases.

In this study of MR imaging with a surface coil, a linear relation between the measured signal intensity and the histopathologically proved pigmentation in uveal melanoma was found.

A reliable prediction of the degree of pigmentation within the tumorous areas was possible by using quantitative evaluation of the signal intensities on T1-weighted images. Diagnostic errors occur less frequently with quantitative MR imaging–based evaluation than with visual evaluation. The determination of pigmentation degree with T2-weighted imaging was less reliable than with T1-weighted imaging, possibly because of the lower spatial resolution and higher susceptibility to motion artifacts at T2 imaging.

A mixed melanomatous pigmentation was found in about a fifth of the patients, and this could be observed only with MR imaging before surgery. In these cases, representative results could not be obtained with ophthalmoscopy, because the other part of the tumor was not visible.

Intravenous contrast material injection facilitated moderate to strong enhancement and thus resulted in the identification of melanoma and in the differentiation between tumor and retinal detachment in all patients.



View larger version (169K):
[in this window]
[in a new window]
  		Figure 3a. Moderately pigmented choroidal melanoma of the left eye in a 69-year-old patient. In a–d, ant. = anterior direction, L = lens, R = retina, S = sclera, temp. = temporal direction, V = vitreous body. (a) Axial T1-weighted image (600/20, 256 x 256 matrix, two acquisitions) shows a large moderately hyperintense tumor (M) in the nasal (nas.) part of the eye that has little inhomogeneous texture and virtually fills the entire eye; the tumor is near but does not infiltrate the optic disk. The retinal detachment (D) and tumor have nearly identical signal intensities. (b) Axial T2-weighted image (2,300/90, 240 x 256 matrix, one acquisition) shows small areas of hypointensity within the tumor (M) compared with the signal intensity in the vitreous body (V); however, the retinal detachment (D) is isointense to the vitreous body. (c) Ophthalmoscopic image shows a semidark tumor (M) in the center of the image, with extended retinal detachment (D). A small part of the normal retina and choroid in the cranial (cran.) direction is visible. (d) Histopathologic preparation (hematoxylin-eosin stain; original magnification, x200) of an axial section shows the tumor near the optic disk (O), an absence of optic nerve infiltration, and moderate pigmentation of the melanoma (M).

 



View larger version (131K):
[in this window]
[in a new window]
  		Figure 3b. Moderately pigmented choroidal melanoma of the left eye in a 69-year-old patient. In a–d, ant. = anterior direction, L = lens, R = retina, S = sclera, temp. = temporal direction, V = vitreous body. (a) Axial T1-weighted image (600/20, 256 x 256 matrix, two acquisitions) shows a large moderately hyperintense tumor (M) in the nasal (nas.) part of the eye that has little inhomogeneous texture and virtually fills the entire eye; the tumor is near but does not infiltrate the optic disk. The retinal detachment (D) and tumor have nearly identical signal intensities. (b) Axial T2-weighted image (2,300/90, 240 x 256 matrix, one acquisition) shows small areas of hypointensity within the tumor (M) compared with the signal intensity in the vitreous body (V); however, the retinal detachment (D) is isointense to the vitreous body. (c) Ophthalmoscopic image shows a semidark tumor (M) in the center of the image, with extended retinal detachment (D). A small part of the normal retina and choroid in the cranial (cran.) direction is visible. (d) Histopathologic preparation (hematoxylin-eosin stain; original magnification, x200) of an axial section shows the tumor near the optic disk (O), an absence of optic nerve infiltration, and moderate pigmentation of the melanoma (M).

 



View larger version (101K):
[in this window]
[in a new window]
  		Figure 3c. Moderately pigmented choroidal melanoma of the left eye in a 69-year-old patient. In a–d, ant. = anterior direction, L = lens, R = retina, S = sclera, temp. = temporal direction, V = vitreous body. (a) Axial T1-weighted image (600/20, 256 x 256 matrix, two acquisitions) shows a large moderately hyperintense tumor (M) in the nasal (nas.) part of the eye that has little inhomogeneous texture and virtually fills the entire eye; the tumor is near but does not infiltrate the optic disk. The retinal detachment (D) and tumor have nearly identical signal intensities. (b) Axial T2-weighted image (2,300/90, 240 x 256 matrix, one acquisition) shows small areas of hypointensity within the tumor (M) compared with the signal intensity in the vitreous body (V); however, the retinal detachment (D) is isointense to the vitreous body. (c) Ophthalmoscopic image shows a semidark tumor (M) in the center of the image, with extended retinal detachment (D). A small part of the normal retina and choroid in the cranial (cran.) direction is visible. (d) Histopathologic preparation (hematoxylin-eosin stain; original magnification, x200) of an axial section shows the tumor near the optic disk (O), an absence of optic nerve infiltration, and moderate pigmentation of the melanoma (M).

 



View larger version (135K):
[in this window]
[in a new window]
  		Figure 3d. Moderately pigmented choroidal melanoma of the left eye in a 69-year-old patient. In a–d, ant. = anterior direction, L = lens, R = retina, S = sclera, temp. = temporal direction, V = vitreous body. (a) Axial T1-weighted image (600/20, 256 x 256 matrix, two acquisitions) shows a large moderately hyperintense tumor (M) in the nasal (nas.) part of the eye that has little inhomogeneous texture and virtually fills the entire eye; the tumor is near but does not infiltrate the optic disk. The retinal detachment (D) and tumor have nearly identical signal intensities. (b) Axial T2-weighted image (2,300/90, 240 x 256 matrix, one acquisition) shows small areas of hypointensity within the tumor (M) compared with the signal intensity in the vitreous body (V); however, the retinal detachment (D) is isointense to the vitreous body. (c) Ophthalmoscopic image shows a semidark tumor (M) in the center of the image, with extended retinal detachment (D). A small part of the normal retina and choroid in the cranial (cran.) direction is visible. (d) Histopathologic preparation (hematoxylin-eosin stain; original magnification, x200) of an axial section shows the tumor near the optic disk (O), an absence of optic nerve infiltration, and moderate pigmentation of the melanoma (M).

 


   Footnotes
 
Supported in part by grant 70-01847-Ho1, Deutsche Krebshilfe.

Address reprint requests to A.J.L.

Author contributions: Guarantors of integrity of entire study, N.H., R.F.; study concepts and design, A.J.L., N.H.; definition of intellectual content, N.H.; literature research, A.J.L., M.R.; clinical studies, A.J.L., C.S.; data acquisition and analysis, A.J.L., M.R.; statistical analysis, A.J.L., M.R.; manuscript preparation and editing, A.J.L.; manuscript review, N.B., N.E.B., R.F., N.H., A.S.

Received October 31, 1997; revision requested January 20, 1998; revision received July 13, 1998; accepted September 9, 1998.
   References
TOP
 Abstract
 Introduction
 MATERIALS AND METHODS
 RESULTS
 DISCUSSION
 References
 

  1. Egan KM, Seddon JM, Glynn RJ, Gragoudas ES, Albert DM. Epidemiologic aspects of uveal melanoma. Surv Ophthalmol 1988; 32:239-251.[Medline]
  2. Tong KA, Osborn AG, Mamalis N, Harrie RP, Call NB. Ocular melanoma. AJNR 1993; 14:1359-1366.[Abstract]
  3. Hungerford J. Uveal melanoma. Eur J Cancer 1993; 29:1365-1368.
  4. Mahoney MC, Burnett WS, Majerovics A, Tanenbaum H. The epidemiology of ophthalmic malignancies in New York State. Ophthalmology 1990; 97:1143-1147.[Medline]
  5. Raivio I. Uveal melanoma in Finland: an epidemiological, clinical, histological and prognostic study. Acta Ophthalmol Suppl 1977; 133:1-64.
  6. Shields CL, Shields JA, De Potter P, Singh AD, Hernandez C, Brady LW. Treatment of non-resectable malignant iris tumours with custom designed plaque radiotherapy. Br J Ophthalmol 1995; 79:306-312.[Abstract/Free Full Text]
  7. Peyman GA, Mafee MF. Uveal melanoma and similar lesions: the role of magnetic resonance imaging and computed tomography. Radiol Clin North Am 1987; 25:471-486.[Medline]
  8. Augsburger JJ, Gamel JW. Clinical prognostic factors in patients with posterior uveal malignant melanoma. Cancer 1990; 66:1596-1600.[Medline]
  9. McLean MJ, Foster WD, Zimmerman LE. Prognostic factors in small malignant melanomas of choroid and ciliary body. Arch Ophthalmol 1977; 95:48-58.[Abstract/Free Full Text]
  10. Mafee MF, Peyman GA. Retinal and choroidal detachments: role of magnetic resonance imaging and computed tomography. Radiol Clin North Am 1987; 25:487-507.[Medline]
  11. Chambers RB, Davidorf FH, McAdoo JF, Chakeres DW. Magnetic resonance imaging of uveal melanomas. Arch Ophthalmol 1987; 105:917-921.[Abstract/Free Full Text]
  12. Frank JA, Dwyer AJ, Girton M, et al. Opening of blood-ocular barrier demonstrated by contrast-enhanced MR imaging. J Comput Assist Tomogr 1986; 10:912-916.[Medline]
  13. Guthoff R, Seiler T. Magnetic resonance tomography in ophthalmologic diagnosis. Fortschr Ophthalmol 1989; 86:343-351.[Medline]
  14. Haik BG, Saint Louis L, Smith ME, Ellsworth RM, Deck M, Friedlander M. Magnetic resonance imaging in choroidal tumors. Ann Ophthalmol 1987; 19:218-222.[Medline]
  15. Zimmerman RA, Bilaniuk LT. Ocular MR imaging (editorial). Radiology 1988; 168:875-876.[Free Full Text]
  16. Foo TK, Shellock FG, Hayes CE, Schenck JF, Slayman BE. High-resolution MR imaging of the wrist and eye with short TR, short TE, and partial-echo acquisition. Radiology 1992; 183:277-281.[Abstract/Free Full Text]
  17. Hosten N, Lemke A, Sander B, et al. MRT of the eye: the normal anatomy and detection of the smallest lesions with a high-resolution surface coil. Fortschr Röntgenstr 1996; 164:126-131[German].
  18. Lemke AJ, Hosten N, Grote A, Felix R. Anatomy and pathology of the retrobulbar space in MRI using a high-resolution surface coil. Der Ophthalmologe 1996; 3:292-298[German].
  19. Schlevogt RK, Mayer UM, Reuther G, Requardt H, Meythaler FH. Nuclear magnetic resonance tomography with surface coils: initial experiences in orbital diagnosis. Klin Monatsbl Augenheilkd 1986; 189:209-213[German].[Medline]
  20. Seiler T, Bende T, Schilling A, Wollensak J. Magnetic resonance tomography in ophthalmology. II. Manifestations of edema of the optic nerve. Klin Monatsbl Augenheilkd 1989; 195:72-78[German].
  21. Shellock FG, Schatz CJ. Increased corneal temperature caused by MR imaging of the eye with a dedicated local coil. Radiology 1992; 185:697-699.[Abstract/Free Full Text]
  22. Mafee MF, Peyman GA, Grisolano JE, et al. Malignant uveal melanoma and simulating lesions: MR imaging evaluation. Radiology 1986; 160:773-780.[Abstract/Free Full Text]
  23. Bloom PA, Ferris JD, Laidlaw DA, Goddard PR. Magnetic resonance imaging: diverse appearances of uveal malignant melanomas. Arch Ophthalmol 1992; 110:1105-1111.[Abstract/Free Full Text]
  24. Peyster RG, Augsburger JJ, Shields JA, Hershey BL, Eagle R. Intraocular tumors: evaluation with MR imaging. Radiology 1988; 168:773-779.[Abstract/Free Full Text]
  25. Coleman DJ, Silverman RH, Rondeau MJ, et al. Ultrasonic tissue characterization of uveal melanoma and prediction of patient survival after enucleation and brachytherapy. Am J Ophthalmol 1991; 112:682-688.[Medline]
  26. Fine SL, Straatsma BR, Earle JD, Hawkins BS, McLaughlin JA. Failure of preenucleation radiation to decrease uveal melanoma mortality: the collaborative ocular melanoma study steering committee (letter). Am J Ophthalmol 1989; 107:440-442.[Medline]
  27. Schachat AP. Management of uveal melanoma: a continuing dilemma: collaborative ocular melanoma study group (letter). Cancer 1994; 74:3073-3075.[Medline]
  28. Shields JA. Counseling the patient with a posterior uveal melanoma. Am J Ophthalmol 1988; 106:88-91.[Medline]
  29. Shields JA. Management of uveal melanoma: a continuing dilemma (editorial). Cancer 1993; 72:2067-2068.[Medline]
  30. Bornfeld N. Diagnosis and therapy of malignant melanoma of the uvea (choroid and ciliary body). Ophthalmologe 1992; 89:W61-78.[Medline]
  31. Gomori JM, Grossman RI, Shields JA, Augsburger JJ, Joseph PM, DeSimeone D. Choroidal melanomas: correlation of NMR spectroscopy and MR imaging. Radiology 1986; 158:443-445.[Abstract/Free Full Text]
  32. Adam G, Brab M, Bohndorf K, Günther RW. Gadolinium-DTPA–enhanced MRI of intraocular tumors. Magn Reson Imaging 1990; 8:683-689.[Medline]
  33. Davidorf FH, Chambers RB, Gresak P. False-positive magnetic resonance imaging of a metastatic carcinoma simulating a malignant melanoma. Ann Ophthalmol 1992; 24:391-394.[Medline]
  34. De Potter P, Shields JA, Shields CL, Yannuzzi LA, Fisher YE, Rao VM. Unusual MRI findings in metastatic carcinoma to the choroid and optic nerve: a case report. Int Ophthalmol 1992; 16:39-44.[Medline]
  35. Wilms G, Dralands G, Van Fraeyenhoven L, et al. Magnetic resonance imaging in lesions of the eye globe. J Belge Radiol 1989; 72:165-172.[Medline]
  36. De Potter P, Flanders AE, Shields JA, Shields CL, Gonzales CF, Rao VM. The role of fat-suppression technique and gadopentetate dimeglumine in magnetic resonance imaging evaluation of intraocular tumors and simulating lesions. Arch Ophthalmol 1994; 112:340-348.[Abstract/Free Full Text]
  37. Lucignani G, Paganelli G, Modorati G, et al. MRI, antibody-guided scintigraphy, and glucose metabolism in uveal melanoma. J Comput Assist Tomogr 1992; 16:77-83.[Medline]
  38. Premkumar A, Marincola F, Taubenberger J, Chow C, Venzon D, Schwartzentruber D. Metastatic melanoma: correlation of MRI characteristics and histopathology. JMRI 1996; 6:190-194.
  39. Hosten N, Bornfeld N, Wassmuth R, et al. Uveal melanoma: detection of extraocular growth with MR imaging and US. Radiology 1997; 202:61-67.[Abstract/Free Full Text]
  40. Mafee MF, Linder B, Peyman GA, Langer BG, Choi KH, Capek V. Choroidal hematoma and effusion: evaluation with MR imaging. Radiology 1988; 168:781-786.[Abstract/Free Full Text]
  41. Mihara F, Gupta KL, Murayama S, Lee N, Bond JB, Haik BG. MR imaging of malignant uveal melanoma: role of pulse sequence and contrast agent. AJNR 1991; 12:991-996.[Abstract]



This article has been cited by other articles:


Home page
 RadioGraphicsHome page
W. R. K. Smoker, L. R. Gentry, N. K. Yee, D. L. Reede, and J. A. Nerad
Vascular Lesions of the Orbit: More than Meets the Eye
RadioGraphics, January 1, 2008; 28(1): 185 - 204.
[Abstract] [Full Text] [PDF]

Home page
 Am. J. Neuroradiol.Home page
K. J. Oh, B. J. Kwon, M. H. Han, P. G. Hwang, C. J. Kim, D. G. Na, and K.-H. Chang
MR Imaging Findings of Uveal Leiomyoma: Three Cases
AJNR Am. J. Neuroradiol., January 1, 2005; 26(1): 100 - 103.
[Abstract] [Full Text] [PDF]

This Article
Right arrow Abstract Freely available
Right arrow Figures Only
Right arrow Full Text (PDF)
Right arrow Submit a response
Right arrow Alert me when this article is cited
Right arrow Alert me when eLetters are posted
Right arrow Alert me if a correction is posted
Right arrow Citation Map
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrow reprints & permissions
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Lemke, A.-J.
Right arrow Articles by Felix, R.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Lemke, A.-J.
Right arrow Articles by Felix, R.

HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
RADIOLOGY RADIOGRAPHICS RSNA JOURNALS ONLINE