Construction and analysis of functional network of hemi-brain in patients with brain tumors before and after anesthesia based on resting-state functional magnetic resonance imaging

Abstract

Objective: To construct and analyze the functional network changes of hemi-brain in patients with brain tumor before and after anesthesia by using resting state functional magnetic resonance imaging (rs-fMRI). Methods: A total of 18 right-handed patients were prospectively included (6 males and 12 females). The patients underwent glioma resection in Peking University International Hospital from December 2018 to December 2021, and age ranged from 20 to 65 (45.1±13.6) years, with American Society of Anesthesiologists (ASA) grade of Ⅰ-Ⅱ. MRI scans were performed while the patient was awake and at the depth of surgical anesthesia. The functional network of healthy lateral brain was constructed and analyzed by means of graph theory, and its global and local topological properties were calculated. Global topology attributes included global efficiency (Eg), local efficiency (Eloc), clustering parameters (Cp), length parameter of shortest path (Lp), and small world (SW). Topology attributes of nodes included node degree (ND), node efficiency (NE) and between centrality (BC). The global and nodal topological properties of the hemi-brain network were compared between patients with different hemispherical space occupying under wakefulness and anesthesia. Results: At the awake state, Eloc and Cp in the global topological attributes of hemi-brain network were 0.259±0.007 and 0.197±0.010, respectively, and decreased to 0.242±0.013 and 0.177±0.021, respectively after anesthesia, with statistically significant differences (all P<0.01). The topological attributes of the nodes in hemi-side brain showed that ND, NE and BC were increased in the default mode network-related brain regions, while NE and BC were decreased in the limbic system and subcortical structures. Eloc and Cp were 0.258±0.008 and 0.198±0.008 respectively in the patients with left hemisphere space occupying, and decreased to 0.241±0.011 and 0.177±0.015 respectively after anesthesia, with statistically significant differences (all P<0.01). However, only Eloc decreased in patients with right hemisphere space occupying after anesthesia, and Eloc was 0.260±0.006 and 0.243±0.016 respectively when awake and after anesthesia, with statistically significant differences (P<0.05). The topological attributes of nodes in patients with space occupying in different cerebral hemispheres showed bidirectional changes after anesthesia, and patients with space occupying in the left cerebral hemisphere were more likely to be widely affected after anesthesia. The effects of anesthetic drugs may show hemispheric laterality. If the tumor was in the dominant hemisphere, the compensatory function of the dominant side was more likely to be damaged. Conclusions: During anesthesia-induced loss of consciousness in patients with brain tumors, both the ability to integrate information and the functional connections between local regions are weakened, and some brain regions have functional connection reorganization. The changes of brain network after anesthesia are bidirectional regulation.