[18F]Fluorodeoxyglucose-Positron Emission Tomography in Patients with Medulloblastoma

Abstract

Abstract OBJECTIVE: We evaluated the [18F]fluorodeoxyglucose (FDG) accumulation during positron emission tomography (PET) in patients with medulloblastoma and examined the relationship of intensity of uptake with patient outcome after the initial scan. METHODS: Magnetic resonance imaging and FDG-PET scans of brain and spine were used to assess FDG uptake by visual grade (qualitative analysis) and metabolic activity ratios (Tmax/Gmean and Tmax/Wmean). Patients were divided into two groups based on either confirmation of tumor by biopsy and/or death resulting from progressive disease after the initial FDG-PET scan (Group A) or no intervention for the suspected lesion shown on magnetic resonance imaging after the initial FDG-PET scan but currently alive without evidence of disease (Group B). RESULTS: Twenty-two patients with either recurrent (n = 21) or newly diagnosed (n = 1) medulloblastoma underwent brain (n = 18) or whole-body (n = 4) FDG-PET scans after magnetic resonance imaging evidence of suspected tumor. The median qualitative analysis was 3 (range, 0–4) in 17 Group A patients compared with 0 (range, 0–1) in 5 Group B patients (P = 0.0003). The mean Tmax/Gmean and Tmax/Wmean ratios for 16 Group A patients were 1.3 (range, 0.1–3.8) and 2.10 (range, 0.4–5.2), respectively, compared with 0.80 (range, 0.20–1.5) and 1.3 (range, 0.5–1.9) in 5 Group B patients (P = 0.2 for both parameters, not significant). There was a significant negative correlation between increased FDG uptake and survival. Higher qualitative analysis and Tmax/Wmean were associated with significantly poorer 2-year overall survival after the initial scan (71% versus 15% for qualitative analysis grade of <3 versus ≥3, P = 0.001; 46% versus 0% for Tmax/Wmean ≤2.5 versus –2.5, P = 0.004). CONCLUSION: Increased FDG uptake is observed in medulloblastoma and is correlated negatively with survival.