Cerebrovascular Reactivity

2022 ◽  
Keyword(s):  
Cerebrovascular Reactivity

Artifact removal from neurophysiological signals: impact on intracranial and arterial pressure monitoring in traumatic brain injury

2020 ◽  
Vol 132 (6) ◽  
pp. 1952-1960 ◽  
Author(s):  
Seung-Bo Lee ◽  
Hakseung Kim ◽  
Young-Tak Kim ◽  
Frederick A. Zeiler ◽  
Peter Smielewski ◽  
...  
Keyword(s):  
Traumatic Brain Injury ◽  
Brain Injury ◽  
Neurological Status ◽  
Cerebrovascular Reactivity ◽  
Cerebral Hypoperfusion ◽  
Clinical Parameters ◽  
Artifact Removal ◽  
Clinical Events ◽  
Arterial Blood ◽  
Before And After

OBJECTIVEMonitoring intracranial and arterial blood pressure (ICP and ABP, respectively) provides crucial information regarding the neurological status of patients with traumatic brain injury (TBI). However, these signals are often heavily affected by artifacts, which may significantly reduce the reliability of the clinical determinations derived from the signals. The goal of this work was to eliminate signal artifacts from continuous ICP and ABP monitoring via deep learning techniques and to assess the changes in the prognostic capacities of clinical parameters after artifact elimination.METHODSThe first 24 hours of monitoring ICP and ABP in a total of 309 patients with TBI was retrospectively analyzed. An artifact elimination model for ICP and ABP was constructed via a stacked convolutional autoencoder (SCAE) and convolutional neural network (CNN) with 10-fold cross-validation tests. The prevalence and prognostic capacity of ICP- and ABP-related clinical events were compared before and after artifact elimination.RESULTSThe proposed SCAE-CNN model exhibited reliable accuracy in eliminating ABP and ICP artifacts (net prediction rates of 97% and 94%, respectively). The prevalence of ICP- and ABP-related clinical events (i.e., systemic hypotension, intracranial hypertension, cerebral hypoperfusion, and poor cerebrovascular reactivity) all decreased significantly after artifact removal.CONCLUSIONSThe SCAE-CNN model can be reliably used to eliminate artifacts, which significantly improves the reliability and efficacy of ICP- and ABP-derived clinical parameters for prognostic determinations after TBI.

scholarly journals A novel method of quantifying hemodynamic delays to improve hemodynamic response, and CVR estimates in CO2 challenge fMRI

2021 ◽  
pp. 0271678X2097858
Author(s):  
Jinxia (Fiona) Yao ◽  
Ho-Ching (Shawn) Yang ◽  
James H Wang ◽  
Zhenhu Liang ◽  
Thomas M Talavage ◽  
...  
Keyword(s):  
Arrival Time ◽  
Stress Test ◽  
Low Frequency ◽  
Hemodynamic Response ◽  
Blood Oxygen Level Dependent ◽  
Cerebrovascular Reactivity ◽  
Bold Signal ◽  
Hemodynamic Response Function ◽  
Carbon Dioxide Co2 ◽  
Co2 Challenge

Elevated carbon dioxide (CO2) in breathing air is widely used as a vasoactive stimulus to assess cerebrovascular functions under hypercapnia (i.e., “stress test” for the brain). Blood-oxygen-level-dependent (BOLD) is a contrast mechanism used in functional magnetic resonance imaging (fMRI). BOLD is used to study CO2-induced cerebrovascular reactivity (CVR), which is defined as the voxel-wise percentage BOLD signal change per mmHg change in the arterial partial pressure of CO2 (PaCO2). Besides the CVR, two additional important parameters reflecting the cerebrovascular functions are the arrival time of arterial CO2 at each voxel, and the waveform of the local BOLD signal. In this study, we developed a novel analytical method to accurately calculate the arrival time of elevated CO2 at each voxel using the systemic low frequency oscillations (sLFO: 0.01-0.1 Hz) extracted from the CO2 challenge data. In addition, 26 candidate hemodynamic response functions (HRF) were used to quantitatively describe the temporal brain reactions to a CO2 stimulus. We demonstrated that our approach improved the traditional method by allowing us to accurately map three perfusion-related parameters: the relative arrival time of blood, the hemodynamic response function, and CVR during a CO2 challenge.

scholarly journals Transcranial Doppler Evaluation of the Cerebral Vasculature in Women Patients who Have Migraine with Aura

Pain Medicine ◽  
2020 ◽  
Vol 21 (11) ◽  
pp. 3012-3017
Author(s):  
Igor Petrušić ◽  
Ana Podgorac ◽  
Aleksandra Radojičić ◽  
Jasna Zidverc-Trajković
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Migraine With Aura ◽  
Transcranial Doppler ◽  
Cerebral Blood Flow Velocity ◽  
Cerebral Arteries ◽  
Transcranial Doppler Sonography ◽  
Cerebrovascular Reactivity ◽  
Breath Holding ◽  
Left And Right

Abstract Background Previous studies suggest that increased cerebrovascular reactivity might be a feature of patients who have migraine with aura (MwA). The correlation between the clinical presentation of migraine with aura and transcranial Doppler parameters remains unclear. Objective The main aim of this study was to explore cerebral blood flow, vascular resistance, and cerebrovascular reactivity in women MwA. Also, the relationships between hemodynamic conditions and aura characteristics are examined. Design Cross-sectional study. Setting Headache Center, Neurology Clinic, Clinical Center of Serbia. Subjects Fifty-four women MwA and 49 healthy controls (HCs). Methods Transcranial Doppler sonography examination was used to determine blood flow mean velocity (MV) and pulsatility index (PI), as well as breath-holding index (BHI), in 15 arterial segments comprising the circle of Willis. Results A total of 54 women MwA and 49 HCs were studied. The PIs of all segments of the left and right middle cerebral arteries and the left and right anterior cerebral arteries were significantly higher in MwA with regards to HCs. Also, both the left and right BHIs were significantly higher in MwA than HCs. In addition, MVs of the right vertebral artery and the first segment of the basilar artery were significantly lower in MwA than HCs. Longer duration of migraine aura showed a weak negative correlation with the PI of the left posterior cerebral artery. Conclusions Our findings suggest increased vessel pulsatility, abnormal cerebrovascular reactivity, and decreased cerebral blood flow velocity in several arterial segments of the Willis circle in women MwA.

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