Study on brain structure network of patients with delayed encephalopathy after carbon monoxide poisoning: based on diffusion tensor imaging.

Abstract

Objective: To analyze the network alteration characteristics of brain structure network in patients with delayed encephalopathy after CO poisoning (DEACMP) based on diffusion tensor imaging (DTI), and to explore the structural correlation neuroimaging mechanism of DEACMP cognitive impairment.

Methods: DTI scanning was performed in 33 patients with DEACMP and 25 healthy controls (HCs) who were matched in age and sex. The whole brain was divided into 90 regions by automated anatomical marker templates. The continuous tracing method was used to reconstruct the brain fiber bundle connection and construct the brain structure weighted network. The global and regional properties were computed by graph theoretical analysis. To compare the brain network regional properties between the DEACMP group and the HCs group, two-sample t test (false discovery rate correction, P < 0.05) was utilized. The correlations between the brain structural network properties and clinical parameters were further analyzed.

Results: Both of the two groups were found to follow the efficient small-world characteristics. The shortest path length of the DEACMP group increased (L_p = 0.86 ± 0.05), whereas global efficiency (E_glob = 9.60 ± 2.65) and local efficiency (E_loc = 17.98 ± 3.89) decreased. Moreover, the core nodes of the DEACMP group's default network, highlighting network, central execution network, and visual area, were decreased (P < 0.05, FDR correction). The left amygdala node degree of DEACMP group was positively correlated with MMSE and MoCA scores of the clinical scale (r = 0.863, P = 0.001, r = 0.525, P = 0.021). The node degree value of the left lingual gyrus was positively correlated with MoCA score (r = 0.406, P = 0.019) and negatively correlated with CDR score (r = -0.563, P = 0.016). The efficiency value of the right dorsolateral superior frontal gyrus in the DEACMP group was negatively correlated with the CDR score (r = -0.377, P = 0.031).

Conclusion: By comparing the differences and changes in the topological properties and nodes of the brain structure network between DEACMP group and HCs group, the degree of related brain regions, especially the damage of higher brain functions in DEACMP patients, was verified, which was helpful to understand the cognitive damage caused by CO poisoning and to predict the efficacy of late remodeling. Small-worldness is a dynamic reorganization of the small-world topology and its community structure from the brain network to provide system-wide flexibility and adaptability (Barbey in Trends Cogn Sci 22(1):8-20, 2018). The combination with DTI is helpful for the accurate localization of brain structural damage, especially in DEACMP patients.