Optimisation du protocole d’acquisition de la TEP à la fluorocholine dans la détection des lésions parathyroïdiennes

Abstract

18F-Fluorocholine (FCH) PET/CT shows very promising potential for detection of hyperfunctioning parathyroid tumors. However, the optimal time to perform imaging after FCH administration has not yet been determined and protocols are highly variable. The aim of this study was to qualitatively and quantitatively compare 5, 10, 15, 20 and 60min post-injection acquisition times in patients with primary hyperparathyroidism and equivocal traditional imaging. Thirty-one patients were included. Two observers retrospectively analyzed the five protocols. Any focal increase in FCH uptake was localized and graded on a discrete gradation scale between 1 and 5 to assess the likelihood of hyperfunctioning parathyroid tumors. Gold standard was histopathological findings for the 11 operated patients. Regarding quantitative analysis, ratio of SUVmax of parathyroid foci on SUVmean of thyroid background (as signal-to-noise ratio) were compared between protocols. After injection of 2.5MBq/kg, FCH PET performed 60min post-injection (2min) had the best sensitivity and specificity by lesion (92% and 100% respectively and the best signal-to-noise ratio (median of 2). We suggest performing PET scan 60min after injection, associated with early acquisition so as not to miss a wash-out hyperfunctioning parathyroid tumors.