Abstract
1681
Background: In preparation for 131I ablation, temporary withdrawal of thyroid hormone is commonly used in patients with thyroid cancer after total thyroidectomy. Aim of this study was to characterize brain metabolic abnormalities in these patients,and the relation with mood dysfunction using 18F-fluoro-2-deoxyglucose positron emission tomography (18F-FDG-PET). METHOD: A total of 75 consecutive adult patients(mean age 47.8±10.5 y;women,39.7%) with thyroid carcinoma who had undergone total thyroidectomy were recruited for this cross-sectional study. All of them were hypothyroid after four weeks of thyroid hormone withdrawal. FDG-PET brain imaging and a completed mood questionaires were performed.Images were analyzed using statistical parametric mapping(SPM5).Using analysis of covariance,all FDG-PET brain images of thyroid patients were compared to a reference population of 63 healthy subjects matched for age(mean age 49.4±9.4 y;p=0.36) and gender(women,54.7%;p=0.08). Multivariate spatial covariance analysis was applied for the image data. RESULTS: In comparison with healthy subjects, the multivariate covariance analysis showed increases in glucose metabolism primarily in the bilateral thalamus,right limibic lobe(BA 27 and 30),right temporal lobe(BA 21) and concomitant decreases in the bilateral parietal lobe(BA 3 and 7) ,left frontal lobe(BA 10) , right frontal lobe(BA 4) in the hypothyroid group (p<0.001) .HAMA tests showed the hypothyroid patients were more depressed than the healthy participants. CONCLUSIONS: Our results identified a peculiar spatial pattern of a cerebral abnormal glucose metabolism and related affective symptoms in thyroid cancer patients before 131I ablation.Future studies are needed to determine whether this pattern could represent a diagnostic biomarker of thyroid cancer patients in hypothyroidism status with depression emotion.