Use of near-infrared spectroscopy to probe occlusion severity in patients diagnosed with carotid atherosclerotic disease

Abstract

Abstract:Atherosclerotic disease has been associated with increased risk of severe neurovascular consequences including transient ischemic attacks, ischemic strokes, and even mortality. Following the onset of carotid stenosis, the brain undergoes different compensatory mechanisms to provide adequate perfusion in order to maintain brain metabolism. In this study, we employed near-infrared spectroscopy (NIRS) to better comprehend how carotid stenosis affects cerebral hemodynamics, both at rest and during activity. Eighteen patients diagnosed with atherosclerotic disease were recruited for a protocol consisting of resting state and vasoreactivity testing performed with breath holding. Although the breath holding challenge induced global vasodilation in all patients, the extent of dilation varied according to the level of stenosis. Patients diagnosed with carotid stenosis have impaired hemodynamic response, with a median 77% vasoreactivity in the hemisphere ipsilateral to the stenotic vessel when compared to the healthy hemisphere. Hemodynamics of these patients differed at rest, with 33% fewer network links in the hemisphere ipsilateral to the stenosis than the healthy hemisphere. On the other hand, hemodynamic patterns were more heterogeneous with patients diagnosed with a carotid occlusion, which correlates with the opening of collateral circulation. Overall, our results suggest that NIRS can open new directions to the investigation of the effects of cerebrovascular atherosclerotic disease.

Integration of Spatial Information Increases Reproducibility in Functional Near-Infrared Spectroscopy

“…After the fNIRS data collection, we first removed channels with a low signal-to-noise ratio (SNR), defined as SNR < 8. We computed the SNR as the mean intensity of each channel divided by the standard deviation of the same channel, and the threshold was chosen based on previous works ( de Oliveira et al, 2017 , 2019 ; Forero et al, 2017 ; Novi et al, 2018 ). Next, we converted light intensity at each wavelength of each channel to optical density (OD) and removed motion artifacts with spline interpolation followed by wavelet decomposition ( Scholkmann et al, 2010 ; Molavi and Dumont, 2012 ; Di Lorenzo et al, 2019 ; Novi et al, 2020 ).…”

“…In the brain, changes in HbO and HbR reflect (at least partially) neural activity due to neurovascular coupling ( Obrig et al, 2002 ; Devor et al, 2005 ; Rovati et al, 2007 ; Mesquita et al, 2009 ; Ou et al, 2009 ; Phillips et al, 2015 ). Due to its high temporal resolution, portability, and versatility, fNIRS has become a suitable choice to investigate brain function non-invasively over a variety of populations, ranging from neonates to adults, both in the healthy and in the diseased brain ( Tsuji et al, 2000 ; Brown et al, 2002 ; Terborg et al, 2004 ; Kim et al, 2010 , 2014 ; Dehaes et al, 2015 ; de Oliveira et al, 2017 , 2019 ; Forero et al, 2017 ; He et al, 2018 ; Forti et al, 2019 ). More recently, wearable technologies have expanded fNIRS protocols to study activities in natural and unconstrained environments ( Piper et al, 2014 ; McKendrick et al, 2016 ; Pinti et al, 2018 ).…”

Effects of Systemic Physiology on Mapping Resting-State Networks Using Functional Near-Infrared Spectroscopy

“…First, channels with a low signal-to-noise ratio (defined as SNR < 8) were removed. This threshold was based on previous experiences with similar systems ( Forero et al, 2017 ; Novi et al, 2020a ). Given the lower number and importance of the SCs in the present work, we also inspected each SC’s power spectrum individually.…”

Desenvolvimento de Novos Métodos para Investigação do Cérebro durante o Estado de Repouso

“…(Note, subjects who were more contaminated by physiological noise naturally present connections with higher correlation values. We have discussed this approach on previous works 3,8 ). Once we had one graph for each run, we combined all graphs of all runs from the same subject, and kept only the links that were presented in at least 50% percent of the runs of each subject.…”

“…In parallel with the advances in fMRI other emerging neuroimaging techniques appeared. One alternative approach to probe brain function is near-infrared spectroscopy (NIRS) 3,4 . Briefly, NIRS employs near-infrared light (~700 -900 nm) to measure hemoglobin concentration changes in the brain noninvasively and with temporal resolution of up to 50 Hz.…”