Shunsuke Satoh, Hidetoshi Ikeda, Toshiyuki Saginoya and Kazuo Watanabe
Objective: To evaluate the usefulness of methionine (MET)-Positron Emission Tomography (PET) for the early diagnosis of Growth Hormone (GH) secreting adenomas, we retrospectively analyzed patients with abnormal GH dynamics and a histologically confirmed GH secreting pituitary adenoma who underwent pre-operative fluorodeoxyglucose-/MET-PET.
Materials and methods: Thirty-two patients with abnormal GH dynamics were included in this study. 3 Tesla (3T) -MRI, [18F]-flurodeoxyglucose (FDG) -/[11C]-MET-PET, and transsphenoidal surgery were performed in all the patients. We determined correlations among FDG-/MET-PET (maximum standardized uptake value (SUVmax)), serum GH and IGF-1 levels, the GH response to a 75 g Oral Glucose Tolerance Test (OGTT), Thyrotropin-Releasing Hormone (TRH) /Luteinizing Hormone-Releasing Hormone (LHRH) loading tests, tumor volume, and proliferative activity.
Results: The diagnostic sensitivity for early GH secreting adenoma was highest for MET-PET (100%), followed by TRH/LHRH (80%), 75 g OGTT (67%), and FDG-PET (47%). Significant correlations were observed between: MET-PET SUVmax and FDG-PET SUVmax (p<0.01), MET-/FDG-PET SUVmax and tumor volume (MET: p<0.01; FDG: p<0.01) ; MET-/FDG PET SUVmax and MIB-1 labeling index (MET: p<0.01; FDG: p=0.01) ; GH/insulin-like growth factor (IGF)-1 levels and tumor volume (GH: p=0.01; IGF-1: p<0.01) ; and GH and IGF-1 levels (p<0.01).
Conclusions: All the patients with abnormal GH dynamics detected by MET-PET had GH adenomas, indicating that MET-PET is useful for the early diagnosis of GH adenomas.PDF
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