TY - JOUR T1 - <strong>Delayed <sup>18</sup>F-FDG hybrid PET/MR improves the diagnostic efficacy for epileptic focus identification: a prospective cohort study</strong> JF - Journal of Nuclear Medicine JO - J Nucl Med SP - 398 LP - 398 VL - 61 IS - supplement 1 AU - FANG LIU AU - Weiwei Ruan AU - Xiaoli Lan Y1 - 2020/05/01 UR - http://jnm.snmjournals.org/content/61/supplement_1/398.abstract N2 - 398Objectives: We sought to investigate the contribution of delayed 18F-FDG imaging data to epileptogenic zone (EZ) identification using a hybrid positron emission tomography / magnetic resonance imaging (PET/MR) system. Methods: Forty-one patients &gt; 12 y with epilepsy underwent a brain dual time point 18F-FDG PET/MRI examination. The patients were divided into: (1) MR-positive (signal/structural abnormalities)/MR-negative depend on MRI findings; (2) extra temporal lobe epilepsy (extra-TLE)/temporal lobe epilepsy (TLE) depend on EZ localization; (3) short delayed (150.1 ± 20.2 min)/long delayed (247.8 ± 24.6 min) by time of delayed imaging acquisition (all early imaging was acquired at approximately 40 min). SUVmean asymmetry index (AI) of dual time points were compared between MR-positive and MR-negative, between extra-TLE and TLE, and between the two delayed imaging intervals. Two observers, who had no knowledge of which images were early or delayed, compared the pairs of early-time-point and delayed-time-point images and selected the image with more obvious difference between the sides for visual evaluation. Results: Among the 41 cases, 38 (92.7%) cases had a larger AI at the delayed time than at the early time post-injection. The SUVmean AI at delayed time points was increased by a mean of 3.7 over the early time point in all (P &lt; 0.01). The ΔAI between two imaging points were 3.71±3.50, 4.67±7.94, 4.52±6.70, 2.51±2.42, 4.24±6.52, 3.46±2.90 respectively for MR-positive, MR-negative, extra-TLE, TLE, short delayed and long delayed group. Among the selected images from these two observers, 85.4% and 82.9%, respectively, were selected as the delay-time-point images. The Kappa value between the two observers was 0.66 with good agreement. Conclusions: Delayed 18F-FDG PET/MRI can be used to better identify EZs with relatively greater metabolic asymmetry between the EZ and contralateral regions, especially in patients with visible MRI abnormalities or extratemporal EZs at short delayed time. ER -