scholarly journals Quantification of Hypoperfusion in Autism Assessed by Diffuse Correlation Spectroscopy and Frequency Domain Near Infrared Spectroscopy

2020 ◽  
Author(s):  
Benjamin Rinehart ◽  
Chien-Sing Poon ◽  
Ulas Sunar
Keyword(s):  
Blood Flow ◽  
Near Infrared ◽  
Correlation Spectroscopy ◽  
Emission Tomography ◽  
Control Group ◽  
Resonance Imaging ◽  
Diffuse Correlation Spectroscopy ◽  
Autistic Group ◽  
Positron Emission ◽  
Lower Blood

AbstractThere is a need for quantitative biomarkers for early diagnosis of autism. We showed previously that hemoglobin concentrations show contrast between autistic group vs control group in humans. Cerebral blood flow can provide additional sensitivity for improved characterization. Diffuse correlation spectroscopy (DCS) has been shown to be reliable method to obtain blood flow contrast in animals and humans. Thus, in this study we evaluated DCS in an established autism model. Our results indicate that autistic group had significantly lower blood flow compared to control group. These results confirm the previous results obtained from humans by positron emission tomography and magnetic resonance imaging.

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

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.

A Review on Brain Imaging Techniques for BCI Applications

2016 ◽  
pp. 39-70
Author(s):  
Saugat Bhattacharyya ◽  
Anwesha Khasnobish ◽  
Poulami Ghosh ◽  
Ankita Mazumder ◽  
D. N. Tibarewala
Keyword(s):  
Magnetic Resonance Imaging ◽  
Positron Emission Tomography ◽  
Magnetic Resonance ◽  
Brain Imaging ◽  
Near Infrared ◽  
Emission Tomography ◽  
Resonance Imaging ◽  
Functional Near Infrared Spectroscopy ◽  
Positron Emission ◽  
The Brain

Evolution has endowed human race with the most adroit brain, and to harness its potential to the fullest the concept of brain computer interface (BCI) has emerged. One of the most crucial components of BCI is the technique of brain imaging. The first approach in the field of brain imaging was to measure the electrical and magnetic activity of the brain, the techniques being known as Electroencephalography and Magnetoencephalography. Striving for furtherance, researchers came up with another alternative known as Magnetic Resonance Imaging. But it being confined to only structural imaging, the functional aspects of brain were mapped using functional magnetic resonance imaging. A similar but comparatively newer neuroimaging modality is Functional Near Infrared Spectroscopy. Transcranial Magnetic Stimulation neuro-physiological technique is based on the principle of electromagnetic induction. Based on nuclear medicine the brain imaging technologies that are widely explored in the world of BCI are Positron Emission Tomography and Single Positron Emission Tomography.

scholarly journals Portable Near-Infrared Technologies and Devices for Noninvasive Assessment of Tissue Hemodynamics

2019 ◽  
Vol 2019 ◽  
pp. 1-11 ◽  
Author(s):  
Lin Hou ◽  
Yinqiu Liu ◽  
Lixia Qian ◽  
Yucong Zheng ◽  
Jinnan Gao ◽  
...  
Keyword(s):  
Blood Flow ◽  
Flow Measurement ◽  
Near Infrared ◽  
Tissue Oxygenation ◽  
Oxygen Metabolism ◽  
Correlation Spectroscopy ◽  
Tissue Blood Flow ◽  
Diffuse Optical Spectroscopy ◽  
Diffuse Correlation Spectroscopy ◽  
Custom Made

Tissue hemodynamics, including the blood flow, oxygenation, and oxygen metabolism, are closely associated with many diseases. As one of the portable optical technologies to explore human physiology and assist in healthcare, near-infrared diffuse optical spectroscopy (NIRS) for tissue oxygenation measurement has been developed for four decades. In recent years, a dynamic NIRS technology, namely, diffuse correlation spectroscopy (DCS), has been emerging as a portable tool for tissue blood flow measurement. In this article, we briefly describe the basic principle and algorithms for static NIRS and dynamic NIRS (i.e., DCS). Then, we elaborate on the NIRS instrumentation, either commercially available or custom-made, as well as their applications to physiological studies and clinic. The extension of NIRS/DCS from spectroscopy to imaging was depicted, followed by introductions of advanced algorithms that were recently proposed. The future prospective of the NIRS/DCS and their feasibilities for routine utilization in hospital is finally discussed.

scholarly journals Positron Emission Tomography/Magnetic Resonance Hybrid Scanner Imaging of Cerebral Blood Flow Using 15O-Water Positron Emission Tomography and Arterial Spin Labeling Magnetic Resonance Imaging in Newborn Piglets

2015 ◽  
Vol 35 (11) ◽  
pp. 1703-1710 ◽  
Author(s):  
Julie B Andersen ◽  
William S Henning ◽  
Ulrich Lindberg ◽  
Claes N Ladefoged ◽  
Liselotte Højgaard ◽  
...  
Keyword(s):  
Positron Emission Tomography ◽  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Magnetic Resonance ◽  
Arterial Spin Labeling ◽  
Input Function ◽  
Emission Tomography ◽  
Resonance Imaging ◽  
Newborn Piglets ◽  
Positron Emission

Abnormality in cerebral blood flow (CBF) distribution can lead to hypoxic–ischemic cerebral damage in newborn infants. The aim of the study was to investigate minimally invasive approaches to measure CBF by comparing simultaneous 15O-water positron emission tomography (PET) and single TI pulsed arterial spin labeling (ASL) magnetic resonance imaging (MR) on a hybrid PET/MR in seven newborn piglets. Positron emission tomography was performed with IV injections of 20 MBq and 100 MBq 15O-water to confirm CBF reliability at low activity. Cerebral blood flow was quantified using a one-tissue-compartment-model using two input functions: an arterial input function (AIF) or an image-derived input function (IDIF). The mean global CBF (95% CI) PET-AIF, PET-IDIF, and ASL at baseline were 27 (23; 32), 34 (31; 37), and 27 (22; 32) mL/100 g per minute, respectively. At acetazolamide stimulus, PET-AIF, PET-IDIF, and ASL were 64 (55; 74), 76 (70; 83) and 79 (67; 92) mL/100 g per minute, respectively. At baseline, differences between PET-AIF, PET-IDIF, and ASL were 22% ( P < 0.0001) and −0.7% ( P = 0.9). At acetazolamide, differences between PET-AIF, PET-IDIF, and ASL were 19% ( P = 0.001) and 24% ( P = 0.0003). In conclusion, PET-IDIF overestimated CBF. Injected activity of 20 MBq 15O-water had acceptable concordance with 100 MBq, without compromising image quality. Single TI ASL was questionable for regional CBF measurements. Global ASL CBF and PET CBF were congruent during baseline but not during hyperperfusion.

scholarly journals Near-infrared diffuse correlation spectroscopy tracks changes in oxygen delivery and utilization during exercise with and without isolated arterial compression

2020 ◽  
Vol 318 (1) ◽  
pp. R81-R88
Author(s):  
Wesley J. Tucker ◽  
Ryan Rosenberry ◽  
Darian Trojacek ◽  
Belinda Sanchez ◽  
Robert F. Bentley ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Blood Flow ◽  
Radial Artery ◽  
Brachial Artery ◽  
Oxygen Delivery ◽  
Near Infrared ◽  
Correlation Spectroscopy ◽  
Flow Index ◽  
Artery Blood Flow ◽  
Diffuse Correlation Spectroscopy

Near-infrared diffuse correlation spectroscopy (NIR-DCS) is an emerging technology for simultaneous measurement of skeletal muscle microvascular oxygen delivery and utilization during exercise. The extent to which NIR-DCS can track acute changes in oxygen delivery and utilization has not yet been fully established. To address this knowledge gap, 14 healthy men performed rhythmic handgrip exercise at 30% maximal voluntary contraction, with and without isolated brachial artery compression, designed to acutely reduce convective oxygen delivery to the exercising muscle. Radial artery blood flow (Duplex Ultrasound) and NIR-DCS derived variables [blood flow index (BFI), tissue oxygen saturation ([Formula: see text]), and metabolic rate of oxygen ([Formula: see text])] were simultaneously measured. During exercise, both radial artery blood flow (+51.6 ± 20.3 mL/min) and DCS-derived BFI (+155.0 ± 82.2%) increased significantly ( P < 0.001), whereas [Formula: see text] decreased −7.9 ± 6.2% ( P = 0.002) from rest. Brachial artery compression during exercise caused a significant reduction in both radial artery blood flow (−32.0 ± 19.5 mL/min, P = 0.001) and DCS-derived BFI (−57.3 ± 51.1%, P = 0.01) and a further reduction of [Formula: see text] (−5.6 ± 3.8%, P = 0.001) compared with exercise without compression. [Formula: see text] was not significantly reduced during arterial compression ( P = 0.83) due to compensatory reductions in [Formula: see text], driven by increases in deoxyhemoglobin/myoglobin (+7.1 ± 6.1 μM, P = 0.01; an index of oxygen extraction). Together, these proof-of-concept data help to further validate NIR-DCS as an effective tool to assess the determinants of skeletal muscle oxygen consumption at the level of the microvasculature during exercise.

scholarly journals Changes in cerebral oxygenation and cerebral blood flow during hemodialysis – A simultaneous near-infrared spectroscopy and positron emission tomography study

2018 ◽  
Vol 40 (2) ◽  
pp. 328-340 ◽  
Author(s):  
Harmke A Polinder-Bos ◽  
Jan Willem J Elting ◽  
Marcel JH Aries ◽  
David Vállez García ◽  
Antoon TM Willemsen ◽  
...  
Keyword(s):  
Positron Emission Tomography ◽  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Infrared Spectroscopy ◽  
Oxygen Content ◽  
Near Infrared Spectroscopy ◽  
Near Infrared ◽  
Emission Tomography ◽  
Positron Emission ◽  
Relative Change

Near-infrared spectroscopy (NIRS) is used to monitor cerebral tissue oxygenation (rSO2) depending on cerebral blood flow (CBF), cerebral blood volume and blood oxygen content. We explored whether NIRS might be a more easy applicable proxy to [15O]H2O positron emission tomography (PET) for detecting CBF changes during hemodialysis. Furthermore, we compared potential determinants of rSO2 and CBF. In 12 patients aged ≥ 65 years, NIRS and PET were performed simultaneously: before (T1), early after start (T2), and at the end of hemodialysis (T3). Between T1 and T3, the relative change in frontal rSO2 (ΔrSO2) was −8 ± 9% ( P = 0.001) and −5 ± 11% ( P = 0.08), whereas the relative change in frontal gray matter CBF (ΔCBF) was −11 ± 18% ( P = 0.009) and −12 ± 16% ( P = 0.007) for the left and right hemisphere, respectively. ΔrSO2 and ΔCBF were weakly correlated for the left (ρ 0.31, P = 0.4), and moderately correlated for the right (ρ 0.69, P = 0.03) hemisphere. The Bland-Altman plot suggested underestimation of ΔCBF by NIRS. Divergent associations of pH, pCO2 and arterial oxygen content with rSO2 were found compared to corresponding associations with CBF. In conclusion, NIRS could be a proxy to PET to detect intradialytic CBF changes, although NIRS and PET capture different physiological parameters of the brain.

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