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

Abstract

Background The narrowing of the carotid arteries with plaque formation represents a major risk factor for ischemic stroke and cognitive impairments. Carotid angioplasty and stenting is a standard clinical treatment to reduce stroke risk. The cognitive effect of carotid angioplasty and stenting remains largely unknown. Purpose This study aims to provide direct evidence of possible effects of carotid angioplasty and stenting on cognition, using task-phase functional magnetic resonance imaging. Material and Methods This study received harmonized institutional ethics board approval (Grant number REB ID =H18-02495/FHREB 2018-058). Two patients had MRI scans pre-carotid angioplasty and stenting and two-month post-carotid angioplasty and stenting. Case 1 had severe (>95%) flow-limiting stenosis in the right carotid artery. Case 2 had 70% non-flow limiting stenosis in the left carotid artery. At each scan, patients completed two functional magnetic resonance imaging sessions while performing a working memory task. Accuracy, reaction time, and brain activation were analyzed for each patient for possible pre-post carotid angioplasty and stenting changes. Results Case 1 showed increased activation in the right (treated-side) frontal and temporal lobes post-carotid angioplasty and stenting; associated with improvements in accuracy (from 58% to 74%) and task completion rate (from 17% to 72%). Case 2 completed the tasks pre- and post-carotid angioplasty and stenting with >90% accuracy, while decreased functional magnetic resonance imaging activation in the contralateral (untreated) hemisphere and mildly increased activation in the left (treated -side) anterior circulation territory were observed post-carotid angioplasty and stenting. Conclusion These cases provided the first task-phase functional magnetic resonance imaging data demonstrating that carotid angioplasty and stenting improved cognitive function in the re-perfused vascular territory. The finding supports the role of carotid angioplasty and stenting in improving cognitive performance beyond reducing stroke risk.

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 ).…”

“…The mean age of patients across the studies was 71.2 ± 7.7 years (median = 71.4), whereas the sex ratio of the research patients was male predominated, ranging from 70 to 100% (mean = 82.0 ± 12.5 %, median = 79.5%). Most of the studies were done on asymptomatic patients (Cheng et al., 2012 ; Huang et al., 2018 ; Lin et al., 2016 ; Porcu et al., 2019 ; Porcu et al., 2021 ; Wang et al., 2017 ); one study investigated only symptomatic patients (Lin et al., 2016 ); one study investigated both symptomatic and asymptomatic patients (Chinda et al., 2021 ). Only a couple of the studies (Cheng et al., 2012 ; Lin et al., 2016 ) carried out analyses of imaging findings and cognitive assessments blinded to diagnosis and treatment (Table 1A ).…”

“…Various brain regions and cognitive domains were examined in the studies under review. The task‐phase study involved the administration of a higher‐level working memory task and examined the prefrontal cortex in a small sample (Chinda et al., 2021 ). Most of the resting‐phase studies examined the default mode network components; although several studies also examined brain regions including the dorsal attention, somatosensory, and salience networks (Table 1B ).…”

“…Chinda et al. ( 2021 ) reported the initial and thus far the only fMRI findings with the use of a cognitive task in two carotid stenosis patients who underwent clinical CAS interventions. The study utilized a delayed match‐to‐sample working memory task with two difficulty levels and cognitive testing using the central nervous system (CNS) vital signs (Gualtieri & Johnson, 2006 ).…”

“…The resting‐state studies reported a change in the scale/pattern of the functional connectivity in brain regions including the default mode, sensorimotor, salience, frontoparietal, and visual networks (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 ). Task‐phase fMRI identified increased strength/level of brain activation and increased hemispherical symmetry in the prefrontal cortex in response to higher‐level cognitive stimuli (Chinda et al., 2021 ). Such effect was seen in the short term (i.e., within 3 months posttreatment) (Cheng et al., 2012 ; Lin et al., 2016 ; Porcu et al., 2019 ; Wang et al., 2017 ).…”