A Prospective Analysis Of 18F-FDG PET/CT In Patients With Uveal Melanoma: Comparison Between Metabolic Rate Of Glucose (MRglu) And Standardized Uptake Value (SUV) And Correlations With Histopathological Features

PurposeTo evaluate whether standardized uptake value (SUV) and/or metabolic rate of glucose (MRglu) are different among epithelioid, mixed, and spindle cell uveal melanomas, as well as between low and high risk melanomas; to correlate ultrasonographic data and metabolic parameters with histopathological features; and to assess the role of 18F-FDG PET/CT for evaluating prognosis.MethodsOf 34 eligible patients prospectively enrolled with clinical suspicion of medium/large uveal melanoma, 26 (15 men, mean age 62.8 ± 11.8 years) were evaluated. All patients underwent metastatic work-up, 3-D dynamic brain and whole-body 18F-FDG PET/CT, and surgery.ResultsOf the 26 ocular lesions, 23 showed 18F-FDG uptake, with a sensitivity of 88 %. MRglu was significantly higher in the epithelioid cell melanomas than in the spindle cell melanomas, as well as in high-risk lesions than in low-risk lesions (p = 0.01, p = 0.02, respectively). SUV and MRglu were correlated with histopathological features while ultrasonographic data were not.ConclusionMRglu is useful for distinguishing the different cell types in uveal melanoma, as well as high-risk from low-risk lesions, while SUV is not. MRglu provides a more accurate evaluation of glucose consumption, whereas SUV provides only an estimation. In addition, the metabolic parameters correlate with histopathological features, well also reflecting cellular behaviour in ocular malignancy. A longer follow-up is needed to assess the role of 18F-FDG in evaluating prognosis.