The Impact of Metabolic Activity of Vertebra and Amygdala on Stroke Recurrence

Background: We investigated whether the metabolic activities of the vertebrae and amygdala are related to future vascular events after cerebral infarction. Methods: Between August 1, 2015 and February 28, 2020 patients admitted with acute cerebral infarction and carotid atherosclerosis were included. They underwent whole-body 18F-fluorodeoxyglucose positron emission tomography (FDG PET). We compared the FDG uptake in the internal carotid artery, vertebrae, spleen and amygdala between patients with and without stroke recurrence. Cox proportional hazards model was used to identify factors related to stroke recurrence. Findings: A total of 110 stroke patients were included (mean age=73 years, 43 female). During the median follow-up period of 18 months, 15 patients experienced stroke recurrence. Patients with recurrent stroke were more likely to have diabetes mellitus, lower estimated glomerular filtration rate, and a higher degree of internal carotid artery stenosis than in those without. Patients with recurred stroke also had a significantly higher glucose uptake in the vertebrae (1·14±0·28 versus 1·36±0·40, p=0·009 by t-test) and amygdala (1·01±0·11 versus 1·09±0·14, p=0·017) than those without. The vertebral FDG uptake correlated with bone mineral density and C-peptide level. The FDG uptake in the amygdala was correlated with the monocyte lymphocyte ratio, but not with the vertebral FDG uptake. The Cox proportional hazard model showed that a higher FDG uptake in the vertebrae was independently associated with stroke recurrence (hazard ratio=4·94, 95% confidence interval=1·29 – 18·9), and a higher FDG uptake in the amygdala with overall vascular events (hazard ratio=3·11, 95% confidence interval=1·11 – 8·70). Interpretation: The increased metabolic activities of the vertebrae and amygdala are related to stroke recurrence and overall vascular event, possibly by elevated insulin resistance and innate immune response. Funding Statement: The study was supported by the Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education (NRF- 2019R1F1A1059455). Declaration of Interests: None. Ethics Approval Statement: This study was reviewed and approved by the institutional review board of Chung-Ang University Hospital (C2015061) and was registered in the Clinical Research Information Service (Registration no.: 170602-001) as a part of the International clinical Trials Registry Platform of the World Health Organization supported by Korea centers for Disease Control and Prevention.