Changes Of Brain Functional Connectivity Strength In Patients After Thyroidectomy Under General Anesthesia Using Resting-state Functional MRI

Objective: To compare the strength of intrinsic connectivity alternations at resting-state in patients undergoing general anesthesia using the graph theory analysis method,based on the voxel level of the functional connectivity(FC)strength.Method: In our hospital,20 patients with thyroidectomy who were older than 55 years old underwent resting-state functional MRI(rs-fMRI)examinations on the day before operation(preoperative group)and 3 days after operation(postoperative group).Data of rs-fMRI were measured on SPM8(based on Matlab station),including correction for time,space,head movement,space standardization and smoothing processing.Space standardization template used was the Montreal Neurological Institute(MNI)template default used in SPM software.Data was analyzed using REST for wave filtering and linear drift removal.SPM8 software was used to calculate the FC strength of each voxel at the whole brain level.The intragroup comparison was performed using a single sample t test.Paired sample t test was used for comparison between groups.Results: Compared with the preoperative data,there were generally FC increase or reduction in patients after surgery.The most significant point in the increasing region was Right mid occipital gyrus and Right sup occipital gyrus.The most significant point in the decreasing region was in Bilateral supplementary motor area,Right dorsolateral supra-frontal gyrus,Right median frontal gyrus,Bilateral medial cingulate gyrus and Bilateral medial superior frontal gyrus.Conclusion: Brain FC network in middle-aged patients undergoing general anesthesia has changed dramatically,which manifests as a increase or decrease in the FC of multiple brain functional areas.fMRI can be used as an early screening method for brain dysfunction after general anesthesia in middle-aged patients.