Hell J Nucl Med
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Differentiation of vertebral metastases from Schmorl's nodes, especially with fluorine-18-fluorodeoxyglucose (18F-FDG) uptake, is very important for the appropriate management of these patients in case they have malignancy. We aimed to evaluate the value of 18F-FDG positron emission tomography/computed tomography (PET/CT) in differentiating vertebral metastases from Schmorl's nodes with 18F-FDG uptake. ⋯ Although the SUVmax in the Schmorl's nodes and vertebral metastases was similar, the 18F-FDG distribution characteristic in PET/CT can help differentiating the vertebral metastases from Schmorl's.
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In nearly 20%-30% of patients with differentiated thyroid carcinoma (DTC) relapse and 7% of them die during the next 10 years after initial diagnosis. In 10%-30% of patients with DTC after ablation therapy during the follow-up show a negative iodine-131 (131I) whole-body screening test (131I WBS) and increased serum thyroglobulin (Tg) level. Loss of ability of DTC metastatic lesions to trap 131I is associated with pure survival and often aggressive disease. Several studies have shown that in DTC cases non trapping 131I, fluorine-18-fluorodeoxyglucose positron emission tomography (18F-FDG PET) can detect recurrence or metastases with high sensitivity (80%-90%). The purpose of this study was to investigate the clinicopathologic features and other related risk factors of patients with DTC having elevated Tg levels and negative 131I WBS in which recurrence was detected by 18F-FDG PET/CT. We tried to study and stratify patients in this grey zone who could benefit from 18F-FDG PET/CT for the detection of metastases/recurrence according to predefined risk factors not investigated by other researchers. ⋯ The most important factors affecting a true positive 18F-FDG PET/CT study were: ETE, high total 131I dose and the SUVmax values over 4.5.