| BackgroundBreast cancer is one of the most common malignant tumors in women.One of the most important methods to treat breast cancer is chemotherapy,which can significantly improve the survival of patients,but will also cause significant adverse effects such as gastrointestinal reactions,bone marrow suppression and hair loss.In addition,the chemotherapy can lead to cognitive impairment of patients and seriously affect the quality of daily life.The neural mechanisms of cognitive impairment in patients with breast cancer caused by of chemotherapy is not yet clear.New tools based on resting state functional magnetic resonance imaging(rs-f MRI)such asfunctional Connectivity(FC),voxel-mirrored homotopic connectivity(VMHC)and resting state brain network analysis can help to explore the neural mechanisms of cognitive function caused by chemotherapy,which is an important method for the study of cognitive impairment after chemotherapy.ObjectiveTo explore the neuroimaging mechanisms of cognitive dysfunction after chemotherapy in breast cancer patients with the resting state functional magnetic resonance imaging.(1)To explore the changes of brain function caused by chemotherapy and its relationship withexecutive functionimpairment in breast cancer patients based on the seed approach.(2)To explore the changes of resting-state interhemispheric functional connectivity in breast cancer patients after chemotherapy and its relationship with cognitive dysfunction based on VMHC.(3)To explore whether the changes of brain functional network and itsrelationship with cognitive dysfunction based on ICA.Materials and Methods(1)Thirty three breast cancer patients received chemotherapy and 31 matched normal controlswere enrolled in this study.Posterior cingulate cortex(PCC)was choosed as a seed point to observe the whole brain function connection and its relationship with cognitive dysfunction in breast cancer patients.(2)Thirty five patients with breast cancerafter chemotherapy and 32 matched normal controlswere involved in this study.Rs-f MRI was performed and voxel-mirrored homo-connectivity(VMHC)was used to analyze interhemispheric functional connectivity after chemotherapy in breast cancer patients.(3)Thirty six breast cancer patients received chemotherapyand 34 matched normalcontrols were involved in this study.Resting state functional magnetic resonance imaging was performed and independent component analysis was used to identify 8 of the 30 components.These components included the default network,the salient network,the sensory-motor network,the motor network,the attention network,the auditory network,the visual network and the executive control network.The relationship between brain functional network connectivity and cognitive dysfunction in breast cancer patients was also observed.Results(1)Compared with normal controls,function connectivity decrease were found between posterior cingutate and left posterior central gyrus,left anterior central gyrus,right superior temporal gyrus,right cingulate gyrus and right middle frontal gyrus in patients with breast cancer after chemotherapy.The reaction time of number connection test in patients with breast cancer after chemotherapy was negatively correlated with the function connectivity between PCC and the right middle frontal gyrus connectivity(r =-0.565,p= 0.001),and right cingulate gyrus(r =-0.509,p= 0.002).In addition,there is the negative correlation between the reaction time of the Stroop Color-Word Association Test and function connectivity of PCC and the right middle frontal lobe in patients with breast cancer after chemotherapy(r =-0.479,p= 0.005).(2)Breast cancer patients performed significantly less well in tests of memory evaluation(delayed memory)and three sub-tests(Trail Making Test B,Stroop Word Test,and Stroop Control Test)that assessed executive function(p<0.05).The VMHC values of posterior cingutate gyrus,insular lobe,and posterior central gyrus in breast cancer patients were lower than that in health control group(p<0.05).The VMHC value of posterior cingutate gyrus in breast cancer after chemotherapy is significantly correlated with executive function test(Trailmaking B,r=0.361,p=0.018),and the VMHC value of the insular lobe is correlated with the memory evaluation(delayed memory,r=0.345,p=0.023)significantly.There is no significant correlation between the value in posterior central gyrus and neuropsychological tests.(3)Compared with healthy controls,the response time of Stroop interference task and digital connection B in patients with breast cancer after chemotherapy is longer(p<0.05)and there is great increase in fatigue test scores(p<0.05).Functional connectivity decreased in default mode network,executive control network,and sensorimotor network.There is significant negative correlation between the founction connectivity of executive control network and the Stroop Interference Test response time(r =-0.430,p =0.009),andwith TMTB response time in breast cancer patients group.And it was also found that the sensory motor network function connection value and fatigue score of the breast cancer patient group were significantly negatively correlated.Conclusion(1)There is abnormal cognitive function and brain functional connectivity in breast cancer patients after chemotherapy.The abnormal functional connection between PCC and frontal cortex may be the neural mechanism of executive function impairment in breast cancer patients after chemotherapy.(2)The values of VMHC decreased in different brain regions including insular,cingulated posteriorand postcentral regions in breast cancer patients after chemotherapy.These change may be the neural basis of cognitive impairment in breast cancer patients after chemotherapy(3)There was executive function change in breast cancer patients after chemotherapy.The function connection of executive control network,default mode network and sensorimotor network was reduced.The abnormal functional connections of these brain networks may be the underlying neural mechanism of cognitive impairment in breast cancer patients after chemotherapy... |
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