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

• Published in: Journal of neurosurgery Vol. 131; no. 6; p. 1709
• Main Authors: Tani, Naoki, Yaegaki, Takahide, Nishino, Akio, Fujimoto, Kenta, Hashimoto, Hiroyuki, Horiuchi, Kaoru, Nishiguchi, Mitsuhisa, Kishima, Haruhiko
• Format: Journal Article
• Language: English
• Published: United States 01.12.2019
• Subjects: Aged; Carotid Artery, External - diagnostic imaging; Carotid Artery, External - surgery; Carotid Stenosis - diagnostic imaging; Carotid Stenosis - surgery; Cerebral Revascularization - instrumentation; Cerebral Revascularization - trends; Cognition - physiology; Humans; Magnetic Resonance Imaging - trends; Male; Middle Aged; Nerve Net - diagnostic imaging; Predictive Value of Tests; Stents; FIQ = full-scale IQ; WMS-R = Wechsler Memory Scale–Revised; MNI = Montreal Neurological Institute; CAS = carotid artery stenting; pDMN = posterior part of DMN; cognitive change; NASCET = North American Symptomatic Carotid Endarterectomy; FC = functional connectivity; ICA = internal carotid artery; vascular disorders; VIQ = verbal IQ; carotid artery stenting; SFG = superior frontal gyrus; rs-fMRI = resting-state functional MRI; functional connectivity; working memory; PIQ = performance IQ; WAIS-III = Wechsler Adult Intelligence Scale III; aDMN = anterior part of DMN; DMN = default mode network; default mode network; MFG = middle frontal gyrus
• ISSN: 1933-0693
• DOI: 10.3171/2018.7.JNS18404

The 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. The 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. Post-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. FC 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).