Near-Infrared, Diffuse-Correlation-Spectroscopy evaluation of cerebral hemodynamics with Acetazolamide challenge in healthy and acute ischemic stroke subjects

2010 ◽  
Author(s):  
Peyman Zirak ◽  
Raquel Delgado-Mederos ◽  
Udo Weigel ◽  
Mehmet Süzen ◽  
Joan Martí-Fàbregas ◽  
...  
Keyword(s):  
Ischemic Stroke ◽  
Acute Ischemic Stroke ◽  
Near Infrared ◽  
Cerebral Hemodynamics ◽  
Correlation Spectroscopy ◽  
Diffuse Correlation Spectroscopy ◽  
Acetazolamide Challenge

Abstract TMP86: Early Microvascular Cerebral Blood Flow Response to Head-of-bed Elevation is Related to Outcome in Acute Ischemic Stroke: A Diffuse Correlation Spectroscopy Study

Stroke ◽  
2017 ◽  
Vol 48 (suppl_1) ◽  
Author(s):  
Clara Gregori-Pla ◽  
Raquel Delgado-Mederos ◽  
Pol Camps-Renom ◽  
Peyman Zirak ◽  
Igor Blanco ◽  
...  
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Ischemic Stroke ◽  
Acute Ischemic Stroke ◽  
Correlation Spectroscopy ◽  
Stroke Onset ◽  
Diffuse Correlation Spectroscopy ◽  
Blood Flow Response ◽  
Poor Outcome ◽  
Flow Response

Introduction: The microvascular cerebral blood flow response (rCBF) to orthostatic stress has been shown to be altered in acute ischemic stroke (AIS) by diffuse correlation spectroscopy (DCS). However, its relevance to the outcome is unknown. Hypothesis: CBF response to head-of-the-bed (HOB) elevation within the first hours after AIS is related to outcome. Methods: Patients with a large anterior circulation stroke of less than 48h from the stroke onset were monitored with DCS to follow rCBF in the frontal lobes during a HOB elevation from supine to 30°. All patients were placed flat during the first 24 hours and later, mobilization was initiated depending on the clinical condition. We categorized measurements as early (<12h) or late (>12h) from stroke onset. NIHSS was recorded at baseline, during HOB, at 24h and 48h. The modified Rankin scale (mRS) score was utilized as the outcome measure (favorable when 0-2). Results: We studied 34 patients (age 78±13y, male 47%, median NIHSS 19 (14-21)) at 16±11 hours from stroke. Ipsilateral extracranial and/or intracranial occlusion was present in 61%. Frontal CBF decreased in both hemispheres after HOB (-5±14%). A paradoxical response (increase/no change) was observed in 18%. rCBF was not correlated to NIHSS and age. Unfavorable outcome was found in 85%. Only at early hours (<12h, n=16), rCBF to HOB elevation in the ipsilateral (not in contralateral) hemisphere (p=0.04, Figure 1) and NIHSS HOB (p=0.008) were associated with poor outcome. Conclusions: This result suggests that paradoxical CBF response to a mild HOB elevation in the early hours of stroke onset is associated with a poor outcome in patients with AIS. Optical continuous monitoring in the bedside may help to individualize management strategies in the early hours of AIS. Figure 1: rCBF due to HOB elevation versus mRS for the ipsi-lateral side in patients measured <12h after stroke.

Diffuse Correlation Spectroscopy for Flow Assessment & Management of Acute Ischemic Stroke

2012 ◽  
Author(s):  
Rickson C. Mesquita ◽  
Steven S. Schenkel ◽  
Turgut Durduran ◽  
Christopher G. Favilla ◽  
Meeri N. Kim ◽  
...  
Keyword(s):  
Ischemic Stroke ◽  
Acute Ischemic Stroke ◽  
Correlation Spectroscopy ◽  
Diffuse Correlation Spectroscopy

scholarly journals Cerebral haemodynamics with head position changes post-ischemic stroke: A systematic review and meta-analysis

2020 ◽  
Vol 40 (10) ◽  
pp. 1917-1933
Author(s):  
Lilian B Carvalho ◽  
Sharon Kramer ◽  
Karen Borschmann ◽  
Brian Chambers ◽  
Vincent Thijs ◽  
...  
Keyword(s):  
Systematic Review ◽  
Ischemic Stroke ◽  
Near Infrared ◽  
Meta Analysis ◽  
Correlation Spectroscopy ◽  
Position Change ◽  
Cerebral Haemodynamics ◽  
Diffuse Correlation Spectroscopy ◽  
Head Positioning ◽  
Head Positions

The effects of upright postures on the cerebral circulation early post-ischemic stroke are not fully understood. We conducted a systematic review and meta-analysis to investigate the effects of head positioning on cerebral haemodynamics assessed by imaging methods post-ischemic stroke. Of the 21 studies included ( n = 529), 15 used transcranial Doppler. Others used near-infrared, diffuse correlation spectroscopy and nuclear medicine modalities. Most tested head positions between 0° and 45°. Seventeen studies reported changes in CBF parameters (increase at lying-flat or decrease at more upright) in the ischaemic hemisphere with position change. However, great variability was found and risk of bias was high in many studies. Pooled data of two studies ≤24 h ( n = 28) showed a mean increase in cerebral blood flow (CBF) velocity of 8.5 cm/s in the ischaemic middle cerebral artery (95%CI,−2.2–19.3) from 30° to 0°. The increase found ≤48 h ( n = 50) was of 2.3 cm/s (95%CI,−4.6–9.2), while ≤7 days ( n = 38) was of 8.4 cm/s (95%CI, 1.8–15). Few very early studies (≤2 days) tested head positions greater than 30° and were unable to provide information about the response of acute stroke patients to upright postures (sitting, standing). These postures are part of current clinical practice and knowledge on their effects on cerebral haemodynamics is required.

Impact of Changes in Tissue Optical Properties on Near-Infrared Diffuse Correlation Spectroscopy Measures of Skeletal Muscle Blood Flow

2021 ◽  
Author(s):  
Miles F. Bartlett ◽  
Scott M. Jordan ◽  
Dennis M. Hueber ◽  
Michael D. Nelson
Keyword(s):  
Skeletal Muscle ◽  
Blood Flow ◽  
Optical Properties ◽  
Near Infrared ◽  
Muscle Blood Flow ◽  
Reactive Hyperemia ◽  
Correlation Spectroscopy ◽  
Skeletal Muscle Blood Flow ◽  
Diffuse Correlation Spectroscopy ◽  
Tissue Optical Properties

Near-infrared diffuse correlation spectroscopy (DCS) is increasingly utilized to study relative changes in skeletal muscle blood flow. However, most diffuse correlation spectrometers assume that tissue optical properties- such as absorption (μa) and reduced scattering (μ's) coefficients- remain constant during physiological provocations, which is untrue for skeletal muscle. Here, we interrogate how changes in tissue μa and μ's affect DCS calculations of blood flow index (BFI). We recalculated BFI using raw autocorrelation curves and μa/μ's values recorded during a reactive hyperemia protocol in 16 healthy young individuals. First, we show that incorrectly assuming baseline μa and μ's substantially affects peak BFI and BFI slope when expressed in absolute terms (cm2/s, p<0.01) but these differences are abolished when expressed in relative terms (% baseline). Next, to evaluate the impact of physiologic changes in μa and μ's, we compared peak BFI and BFI slope when μa and μ's were held constant throughout the reactive hyperemia protocol versus integrated from a 3s-rolling average. Regardless of approach, group means for peak BFI and BFI slope did not differ. Group means for peak BFI and BFI slope were also similar following ad absurdum analyses, where we simulated supraphysiologic changes in μa/μ's. In both cases, however, we identified individual cases where peak BFI and BFI slope were indeed affected, with this result being driven by relative changes in μa over μ's. Overall, these results provide support for past reports in which μa/μ's were held constant but also advocate for real-time incorporation of μa and μ's moving forward.

Cerebral Blood Flow of the Neonatal Brain after Hypoxic-Ischemic Injury

2021 ◽  
Author(s):  
Luis Octavio Tierradentro-García ◽  
Sandra Saade-Lemus ◽  
Colbey Freeman ◽  
Matthew Kirschen ◽  
Hao Huang ◽  
...  
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Near Infrared ◽  
Imaging Modality ◽  
Brain Perfusion ◽  
Correlation Spectroscopy ◽  
Therapeutic Interventions ◽  
Routine Practice ◽  
Diffuse Correlation Spectroscopy ◽  
Positron Emission

Objective Hypoxic-ischemic encephalopathy (HIE) in infants can have long-term adverse neurodevelopmental effects and markedly reduce quality of life. Both the initial hypoperfusion and the subsequent rapid reperfusion can cause deleterious effects in brain tissue. Cerebral blood flow (CBF) assessment in newborns with HIE can help detect abnormalities in brain perfusion to guide therapy and prognosticate patient outcomes. Study Design The review will provide an overview of the pathophysiological implications of CBF derangements in neonatal HIE, current and emerging techniques for CBF quantification, and the potential to utilize CBF as a physiologic target in managing neonates with acute HIE. Conclusion The alterations of CBF in infants during hypoxia-ischemia have been studied by using different neuroimaging techniques, including nitrous oxide and xenon clearance, transcranial Doppler ultrasonography, contrast-enhanced ultrasound, arterial spin labeling MRI, 18F-FDG positron emission tomography, near-infrared spectroscopy (NIRS), functional NIRS, and diffuse correlation spectroscopy. Consensus is lacking regarding the clinical significance of CBF estimations detected by these different modalities. Heterogeneity in the imaging modality used, regional versus global estimations of CBF, time for the scan, and variables impacting brain perfusion and cohort clinical characteristics should be considered when translating the findings described in the literature to routine practice and implementation of therapeutic interventions. Key Points

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