The role of fat-suppression technique and gadopentetate dimeglumine in magnetic resonance imaging evaluation of intraocular tumors and simulating lesions
P. De Potter, A. E. Flanders, J. A. Shields, C. L. Shields, C. F. Gonzales and V. M. Rao
Ocular Oncology Service, Wills Eye Hospital, Philadelphia, PA.
OBJECTIVE: Recent studies have shown that contrast (gadopentetate
dimeglumine)-enhanced magnetic resonance imaging is useful in evaluating
intraocular tumors and differentiating uveal melanoma from other simulating
lesions. The purpose of this study was to study prospectively the role of
fat-suppression technique and gadopentetate dimeglumine-enhanced magnetic
resonance imaging in the evaluation of intraocular neoplasia. PATIENTS:
Forty-three uveal melanomas and 20 other simulating intraocular lesions
from 63 patients were prospectively evaluated on non-contrast-enhanced and
post-contrast-enhanced T1-weighted images with and without fat-suppression
technique and on T2-weighted images. RESULTS: Forty-one uveal melanomas
(95%) were detected with standard pulse sequences and showed the
characteristic hyperintense signal on non-contrast-enhanced T1-weighted
images and hypointense signal with respect to the vitreous on T2-weighted
images. All 33 uveal melanomas evaluated on non-contrast-enhanced
T1-weighted images with fat-suppression technique were detected on
non-contrast-enhanced images with fat-suppression technique. The intensity
of the signal was statistically associated with the degree of pigmentation
of the tumor on T1-weighted images with fat-suppression technique (P =
.03). On post-contrast-enhanced T1-weighted images with or without
fat-suppression technique, the 43 uveal melanomas showed enhancement. The
degree of tumor enhancement was not statistically related to the degree of
tumor pigmentation or the location of the tumor. Among the other simulating
intraocular lesions, choroidal metastasis, retinoblastoma, choroidal
leiomyoma, and medulloepithelioma demonstrated the same features on
magnetic resonance imaging studies as uveal melanoma demonstrated on
non-contrast-enhanced and post-contrast-enhanced T1-weighted images with or
without fat-suppression technique. In our series, choroidal hemangioma,
choroidal osteoma, posterior scleritis, retinal hemangioma, and Coats'
disease can be differentiated from other amelanotic intraocular tumors by
their characteristics on magnetic resonance imaging studies. CONCLUSIONS:
We concluded that pre-and post-contrast-enhanced T1-weighted images with
fat-suppression technique are most helpful in detecting small intraocular
tumors with a thickness of more than 1.8 mm and in evaluating intraocular
neoplasms and simulating lesions, particularly when T2-weighted images are
not available. Moreover, in juxtapapillary choroidal or retinal tumor,
fat-suppression technique may help in the detection of possible optic nerve
or orbital extension by improving the conspicuousness of the tumor.
