Study on tau brain network and asymmetry of Alzheimer′s disease based on 18F-APN-1607 PET imaging / 中华核医学与分子影像杂志

ABSTRACT

Objective:To reveal the abnormal topology of brain network in Alzheimer′s disease (AD), and evaluate the laterality of tau protein deposition in brains of AD patients based on 18F-APN-1607 PET brain imaging combined with graph theory. Methods:From November 2018 to January 2020, 23 clinically diagnosed AD patients (9 males, 14 females; age (61.3±10.7) years) and 13 normal controls (NC) (9 males, 4 females; age (61.6±4.5) years) who underwent 18F-APN-1607 PET imaging in Huashan Hospital, Fudan University were analyzed in this cross-sectional study. The brain network analysis method based on graph theory was used to construct the tau network of the NC group and the AD group, the network attributes (clustering coefficient, shortest path length, local efficiency, and small-worldness) were calculated, and the asymmetry index (AI) of each group to evaluate the laterality of tau protein deposition was obtained. Permutation test (1 000 times) was used to analyze the differences in brain network parameters between the NC group and the AD group. Results:The tau network of the AD group had obvious topological disorder, and the connections in the olfactory cortex and temporal lobe were weakened, while in the posterior cingulate gyrus, anterior wedge, and parietal occipital lobe, the connections were enhanced. Compared with NC group, clustering coefficient ( t values 2.28-2.69), local efficiency ( t values 2.34-3.06) and small-worldness ( t values 2.26-3.32) were significantly decreased in AD group (all P<0.05) with the sparsity of 20%-50%, while the shortest path length was significantly increased ( t values 2.13-2.85; all P<0.05). There was significant tau laterality in the posterior cingulate gyrus, superior parietal gyrus, paracentral lobule, superior temporal gyrus and middle temporal gyrus (AI 10.5%(8.1%, 13.9%), 14.1%(7.6%, 20.3%), -12.4%(-15.7%, -7.8%), -10.8%(-15.3%, -2.1%) , -12.1%(-17.9%, -6.6%), respectively). Conclusion:The tau network analysis based on 18F-APN-1607 may be used to reveal abnormal topological changes of AD patients, and the tau deposition in the posterior cingulate gyrus, superior parietal gyrus, paracentral lobule, superior temporal gyrus and middle temporal gyrus has obvious laterality in AD patients.