title: MR imaging of malignant uveal melanoma: role of pulse sequence and contrast agent.
abstract: To determine the most sensitive pulse sequence and to clarify the role of each pulse sequence in the MR diagnosis of uveal malignant melanoma, noncontrast T1- and T2-weighted, and postcontrast T1-weighted, spin-echo images were compared blindly and independently by two experienced observers. Thirty uveal malignant melanomas, preselected by ophthalmoscopy and sonography for size greater than 2 mm, were examined with a 1.5-T superconducting MR unit with an orbital surface coil. Fifteen tumor studies were done after the patient was injected with gadopentetate dimeglumine. Postcontrast T1-weighted images were the most sensitive in detecting melanomas, demonstrating tumors 2 mm in height accurately on axial planes and 1.6 mm in height on combined orthogonal planes. The contrast-to-noise ratio between melanoma and vitreous fluid was greatest on postcontrast T1-weighted images (average, 72.1), followed by noncontrast T1-weighted images (average, 32.9), and then by T2-weighted images (average, -21.2). Postcontrast T1-weighted images also proved useful in differentiating melanomas from subretinal fluid collections when combined with noncontrast images. We conclude that postcontrast T1-weighted images are most helpful in detecting small uveal melanomas and in differentiating melanomas from subretinal fluid collections.
authors.affiliation: Department of Diagnostic Radiology, University of Maryland Medical System, Baltimore 21201.
authors.forename: F
authors.initials: F
authors.lastname: Mihara
authors.forename: K L
authors.initials: KL
authors.lastname: Gupta
authors.forename: S
authors.initials: S
authors.lastname: Murayama
authors.forename: N
authors.initials: N
authors.lastname: Lee
authors.forename: J B
authors.initials: JB
authors.lastname: Bond
authors.forename: B G
authors.initials: BG
authors.lastname: Haik
mesh_terms: D003287:Contrast Media; D004338:Drug Combinations; D019786:Gadolinium DTPA; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008536:Meglumine; D008545:Melanoma / Q000175:diagnosis*; D009942:Organometallic Compounds; D004369:Pentetic Acid; D014604:Uveal Neoplasms / Q000175:diagnosis*
chemical_list: D003287:Contrast Media; D004338:Drug Combinations; D009942:Organometallic Compounds; D008536:Meglumine; D004369:Pentetic Acid; D019786:Gadolinium DTPA