Functional connectivity analysis and prediction of cognitive change after carotid artery stenting

Abstract

OBJECTIVEThe neurocognitive course of patients who have undergone cerebral revascularization has been the subject of many studies, and the reported effects of carotid artery stenting (CAS) on cognitive function have varied from study to study. The authors hypothesized that cognitive amelioration after CAS is associated with alteration of the default mode network (DMN) connectivity, and they investigated the correlation between functional connectivity (FC) of the DMN and post-CAS changes in cognitive function in order to find a clinical marker that can be used to predict the effect of cerebral revascularization on patients’ cognitive function in this preliminary exploratory study.METHODSThe authors examined post-CAS changes in cognitive function in relation to FC in patients treated for unilateral carotid artery stenosis. Resting-state functional MRI (rs-fMRI) was performed with a 3-T scanner before and 6 months after CAS in 8 patients. Neuropsychological tests (Wechsler Adult Intelligence Scale III and Wechsler Memory Scale–Revised) were administered to each patient before and 6 months after CAS. The DMN was mapped for each patient through independent component analysis of the rs-fMR images, and the correlation between FC of the DMN and post-CAS change in cognitive function was analyzed on a voxel level. Multivariable regression analysis was performed to identify preoperative factors associated with a post-CAS change in cognitive function.RESULTSPost-CAS cognitive function varied between patients and between categories of neuropsychological tests. Although there was no significant overall improvement in Working Memory scores after CAS, post-CAS Working Memory scores changed in negative correlation with changes in FC between the DMN and the precentral/superior frontal gyrus and between the DMN and the middle frontal gyrus. In addition, the preoperative FC between those areas correlated positively with the post-CAS improvement in working memory.CONCLUSIONSFC between the DMN and working memory–related areas is closely associated with improvement in working memory after CAS. Preoperative analysis of FC of the DMN may be useful for predicting postoperative improvement in the working memory of patients being treated for unilateral stenosis of the extracranial internal carotid artery.Clinical trial registration no.: UMIN000020045 (www.umin.ac.jp/ctr/index.htm)

Functional MRI evaluation of the effect of carotid artery stenting: a case study demonstrating cognitive improvement

“…5 Previous research studies relying on only paperbased/adapted routine neurocognitive tests have been largely conflicting in their results. [6][7][8][9] While some studies have utilized resting-state fMRI [10][11][12] to show functional connectivity changes with CAS, our study has the advantage of using task-phase fMRI to map out specific brain areas associated with memory improvement in patients undergoing CAS.…”

“…Studies that utilized functional magnetic resonance imaging (fMRI) have been conducted at resting-phase and showed functional connectivity changes with CAS. [10][11][12] Even so, the resting-state fMRI data lacked the ability to detect the brain functional changes in solving cognitive problems that require the application of task-phase fMRI. Task-phase fMRI as utilized here has provided an objective method of evaluating brain activation as measured by the bloodoxygen level dependent (BOLD) response when paired to specific fMRI tasks such that cerebral recruitment can be spatially and temporally isolated.…”

Functional MRI evaluation of cognitive effects of carotid stenosis revascularization

“…Most studies were conducted using high‐field MRI (3 Tesla), except two that were conducted at 1.5T (Porcu et al., 2019 ; Porcu et al., 2021 ). Only one study applied a cognitive task (Chinda et al., 2021 ), whereas the rest were resting‐state studies (Cheng et al., 2012 ; Huang et al., 2018 ; Lin et al., 2016 ; Porcu et al., 2019 ; Porcu et al., 2021 ; Tani et al., 2018 ; Wang et al., 2017 ). Clinical revascularization interventions included CAS alone (Cheng et al., 2012 ; Chinda et al., 2021 ; Huang et al., 2018 ; Tani et al., 2018 ; Wang et al., 2017 ), CEA alone (Porcu et al., 2019 ), and combined CAS and medical therapy (Lin et al., 2016 ).…”

Cognitive Functions in Patients after Carotid Artery Revascularization—A Narrative Review

“…Moreover, baseline FC between these brain regions correlated positively with post-procedure improvement in working memory. These results served as a basis for concluding that functional connectivity (FC) between the DMN and dependent region working memory was closely associated with post-procedure working memory improvement; consequently, pre-reperfusion FC assessment might anticipate post-reperfusion working memory improvement in patients treated for unilateral stenosis in the ICA [20].…”

“…CAS has been shown to reduce stroke risk in the future, but its effect on cognitive function is uncertain. The vast majority of existing studies report an improvement in neurocognitive abilities after CAS [6][7][8][9][10][11][12][13][14][15][16][17][18][19][20]. One study reports no change [21], while several papers describe a partial or controversial effect [22][23][24].…”