Effect Of Carotid Endarterectomy On Cognitive Impairment In Asymptomatic Severe Carotid Stenosis Patients Based On Magnetic Resonance Imaging

Part 1:Investigate the cognitive impairment in patients with carotid stenosis by using resting-state functional magnetic resonance imaging.Objective:The purpose of this paper was to investigate the mechanisms of cognitive impairment in patients with asymptomatic severe carotid stenosis by using resting-state functional MRI(rs-fMRI).Methods:21 asymptomatic severe carotid artery stenosis patients and 21 normal persons from January 2016 to June 2018 were enrolled and administered cognitive assessment and rs-fMRI in our department.Their cognition and MRI data were analyzed prospectively.Result:Asymptomatic carotid artery stenosis patients' scores in MMSE and MoCA were significantly lower than normal.Patients showed increased ALFF in the right medial superior frontal gyrus,decreasing ALFF in the lingual gyrus,increased fALFF in the left inferior frontal gyrus,increased ReHo in the superior temporal gyrus and decreasing ReHo in the right inferior occipital gyrus than normal.Patients showed increased connectivity to the posterior cingulate cortex(PCC)in the right superior frontal gyrus.There was no correlation between cognitive assessment and imaging date.Conclusion:Asymptomatic severe carotid stenosis could lead different degree of cognitive impairment.The right medial frontal gyrus,left inferior frontal gyrus,superior temporal gyrus,and right superior dorsolateral gyrus may play a significant role in the cognitive impairment.Part 2:The changes of cognitive function,cerebral perfusion and resting state functional MRI after carotid endarterectomy in asymptomatic severe carotid stenosis patients.Objective:The purpose of this paper was to investigate the impact of carotid endarterectomy(CEA)on cognitive function,cerebral perfusion and resting state functional MRI in patients with asymptomatic severe carotid artery stenosis.Methods:18 asymptomatic severe carotid artery stenosis patients from May 2016 to May 2018 were enrolled prospectively and underwent CEA.Cognitive assessment and MRI were accepted 1 week before and 3 months after CEA in our department.Their cognitive function,cerebral perfusion and resting state functional MRI were compared between preoperation and postoperation.Results:All of included 18 patients completed the procedure.After CEA,significant improvement in the scores of the MoCA,California verbal learning test(CVLT),Trail Making Test and Stroop test were found.Significant improvement of cerebral perfusion was also found,including the decrease of relative cerebral blood flow(rCBF),relative cerebral blood volume(rCBV),relative mean transit time(rMTT),time to peak(TTP)and arrive time(TO).Patients showed significantly increased ALFF mainly in the cerebellum and the left precental gyrus,decreased ALFF in the right lingual gyrus,increased fALFF in the left posterior cerbellar lobe and the left middle frontal gyrus,decreased fALFF in the right anterior lobe cerebellum,increased ReHo in the right middle frontal gyrus,decreased ReHo in the right precuneus and fusiform gyrus after CEA.The increased connectivity to the PCC mainly in right precental gyrus was found in patients after CEA.The significant correlation was found between the change of TMT(post-TMT/pre-TMT)and the variation of rCBF(post-rCBF/pre-rCBF)(P<0.01).The significant correlation was also found between the change of stroop test(post-stroop/pre-stroop)and the variation of rCBF(post-rCBF/pre-rCBF)(P<0.01).Conclusion:CEA is a effective treatment for carotid artery stenosis which could improve the cognitive function and cerebral perfusion of severe asymptomatic carotid stenosis patients.Cognitive improvement may be attributed to the reversions of cerebral perfusion and the changes of rs-fMRI.