Resistive index of internal carotid artery and brain networks in patients with chronic cerebral ischemia

About authors

Research Center of Neurology, Moscow, Russia

Correspondence should be addressed: Vitaly F. Fokin
Volokolamskoye shosse 80, Moscow, 125367; ur.liam@fvf

About paper

Author contribution: Fokin VF — study concept, manuscript writing; Ponomareva NV — statistical analysis, manuscript writing; Medvedev RB — duplex ultrasonography, hemodynamic data analysis; Konovalov RN — fMRI data acquisition and analysis; Krotenkova MV — fMRI data analysis, study design; Lagoda OV — clinical data analysis; Tanashyan MM — clinical data analysis, study design.

Compliance with ethical standards: the study was approved by the Ethics Committee of the Research Center of Neurology (protocol № 11/14 dated November 19, 2014); the informed consent was submitted by all patients.

Received: 2021-10-27 Accepted: 2021-11-15 Published online: 2021-11-27

Quantitative assessment of cerebral hemodynamics is important for patients with chronic cerebral ischemia (CCI), as it helps to reveal the pathogenesis of the disease and set the course for effective prevention and treatment. The study was aimed to assess the correlation of the left carotid artery (ICA) resistive index (RI) with cognitive functions and brain network organization based on fMRI data in patients with CCI (51 males and 105 females). The listed above indicators were studied in patients with the left ICA RI values below and above the average (0.54 ± 0.013). The lower, normal physiological ICA resistance levels corresponded to the more successful realization of verbal cognitive functions. In the first group, RI was within normal range (RI = 0.42 ± 0.007), and in the second group RI exceeded normal levels (RI = 0.61 ± 0.01). Variation of the right ICA RI did not correlate with the characteristics of verbal cognitive functions. FMRI data analysis was used to assess the differences in connectivity between various brain regions in the groups with low and high RI. The normal physiological and elevated RI values of the left ICA correlated with differences in the organization of brain networks: normal physiological RI values corresponded to a better organization of hemispheric connections in the basal ganglia and brainstem, and high RI values corresponded to a better organization of connections between the frontal regions and the cerebellum as well as occipital areas of the cerebral cortex. The left ICA RI can be considered as a biomarker of cognitive decline and brain networks reorganization in patients with CCI.

Keywords: neural networks, cognitive functions, chronic cerebral ischemia, internal carotid artery, resistive index