Abstract
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Objectives 18F-FDG-PET with 3D acquisition is used as a potential biomarker for multicenter Alzheimer’s disease (AD) neuroimaging studies, because of the high sensitivity and low radiation exposure. However, the optimal scanning time for 3D-FDG-PET to detect an AD uptake pattern has not been investigated. This study aimed to compare the sensitivity for detecting an AD pattern between early scanning (ES) and late scanning (LS).
Methods The subjects were recruited as clinical AD, MCI or normal in the Japanese AD neuroimaging initiative, and imaged for 30-60 min post-injection of FDG. Three independent experts blinded to the clinical information classified the FDG uptake pattern of the 30-60 min summed images based on criteria proposed by Silverman et al. (JAMA 2001). Target ROIs were defined based on significant differences in FDG uptake between 20 patients with an AD uptake pattern and 20 subjects with a normal pattern. ES and LS images were obtained as data acquired for 30-35 and 55-60 min, respectively. A further 37 patients and 39 normal controls, served as test subjects to evaluate the diagnostic performance, using the Z scores in the target ROIs.
Results FDG uptake in the bilateral frontal lobes was greater in LS than ES, while radioactivity in the venous sinus was greater in ES than LS. However, there were no significant differences between ES and LS (sensitivity: 0.97 vs. 0.97; specificity: 0.82 vs. 0.84; AUC: 0.96 vs. 0.97).
Conclusions For 3D-FDG-PET scanning, it would be beneficial to use an early scanning protocol to detect AD