Blood velocity measurements using laser speckle imaging

Winchester, L. W.; Chou, Nee-Yin

doi:10.1109/iembs.2004.1403397

Cited by 9 publications

(5 citation statements)

References 4 publications

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“…where α is a conversion factor that correlates SFI( i , j ) with the CBF( i , j ), which equals the slope of the linear regression line obtained from the flow phantom experiment (see Supplementary Note 1 ). In previous studies and based on our flow phantom experiment, the results of the LSCI measurement revealed a high correlation and were consistent with flow index ( K 2 ) and absolute flow velocity ( Winchester and Chou, 2004 ; Ambrus et al, 2016 ). Moreover, according to Eq.…”

Section: Methodssupporting

confidence: 87%

Multimodal Optical Imaging to Investigate Spatiotemporal Changes in Cerebrovascular Function in AUDA Treatment of Acute Ischemic Stroke

Wang

Chen

Yang

et al. 2021

Front. Cell. Neurosci.

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Administration of 12-(3-adamantan-1-yl-ureido)-dodecanoic acid (AUDA) has been demonstrated to alleviate infarction following ischemic stroke. Reportedly, the main effect of AUDA is exerting anti-inflammation and neovascularization via the inhibition of soluble epoxide hydrolase. However, the major contribution of this anti-inflammation and neovascularization effect in the acute phase of stroke is not completely elucidated. To investigate the neuroprotective effects of AUDA in acute ischemic stroke, we combined laser speckle contrast imaging and optical intrinsic signal imaging techniques with the implantation of a lab-designed cranial window. Forepaw stimulation was applied to assess the functional changes via measuring cerebral metabolic rate of oxygen (CMRO2) that accompany neural activity. The rats that received AUDA in the acute phase of photothrombotic ischemia stroke showed a 30.5 ± 8.1% reduction in the ischemic core, 42.3 ± 15.1% reduction in the ischemic penumbra (p < 0.05), and 42.1 ± 4.6% increase of CMRO2 in response to forepaw stimulation at post-stroke day 1 (p < 0.05) compared with the control group (N = 10 for each group). Moreover, at post-stroke day 3, increased functional vascular density was observed in AUDA-treated rats (35.9 ± 1.9% higher than that in the control group, p < 0.05). At post-stroke day 7, a 105.4% ± 16.4% increase of astrocytes (p < 0.01), 30.0 ± 10.9% increase of neurons (p < 0.01), and 65.5 ± 15.0% decrease of microglia (p < 0.01) were observed in the penumbra region in AUDA-treated rats (N = 5 for each group). These results suggested that AUDA affects the anti-inflammation at the beginning of ischemic injury and restores neuronal metabolic rate of O2 and tissue viability. The neovascularization triggered by AUDA restored CBF and may contribute to ischemic infarction reduction at post-stroke day 3. Moreover, for long-term neuroprotection, astrocytes in the penumbra region may play an important role in protecting neurons from apoptotic injury.

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Section: Methodssupporting

confidence: 87%

Multimodal Optical Imaging to Investigate Spatiotemporal Changes in Cerebrovascular Function in AUDA Treatment of Acute Ischemic Stroke

Wang

Chen

Yang

et al. 2021

Front. Cell. Neurosci.

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“…ml/s), and the results are expressed as flux measured in arbitrary laser speckle perfusion units (LSPU). Studies using a flow phantom have been performed to validate the technique [10,11]. The phantom consisted of a single tube embedded in a tissue-like substrate to resemble a single blood vessel, and an infusion pump was used to power the actual flow of blood or of solutions with artificial particles.…”

Section: Introductionmentioning

confidence: 99%

Laser Speckle Contrast Imaging for Monitoring Changes in Microvascular Blood Flow

et al. 2016

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Background/Aims: Microvascular blood flow is essential for healing and predicts surgical outcome. The aim of the current study was to investigate the relation between fluxes measured with the laser speckle contrast imaging (LSCI) technique and changes in absolute blood flow. In addition, we studied the reproducibility of the LSCI technique when assessing the intra-abdominal microcirculation of the pig. Methods: During trial 1, a fish gill arch was mechanically perfused with heparinized fish blood under controlled stepwise-altered flow rates alongside mechanically induced movement artefacts. The microcirculation of the fish gill was simultaneously assessed with the LSCI technique. In trial 2, microcirculation was measured in the stomach, liver, and small intestine of 10 pigs by two observers. Results: A linear correlation was observed between flux and volumetric flow. During conditions of no volumetric flow, the high recording speed with the LSCI technique registered the movement artefacts as flow signals. The LSCI measurements showed good correlation and agreement between the two observers when assessing microcirculation in the stomach, liver, and small intestine (r² = 0.857, 0.956, and 0.946; coefficients of variation = 6.0, 3.2, and 6.4%, respectively). Conclusion: Due to the non-contact and real-time assessment over large areas, LSCI is a promising technique for the intraoperative assessment of intra-abdominal microcirculation. A linear correlation between flux and volumetric flow was found, in accordance with previous experimental studies. However, movement artefacts affect flux measurements, and the choice of the sampling speed must be made with care, depending on the given setting.

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“…The use of milk has a number of advantages over the use of blood; specifically, it does not sediment, it is much easier to handle, and presents a behavior similar to intralipid solutions (Waterworth et al 1995, Cubeddu et al 1997. This fluid has also been used in several optical based studies (Wojtkiewicz et al 2009, Figueiras et al 2010, Figueiras 2012, and in some LSCI works (Winchester andChou 2004, Thompson andAndrews 2010). The work from Thompson and Andrews (2010) applied a multi-exposure LSCI to milk, with results similar to those found in red blood cells.…”

Section: Phantommentioning

confidence: 99%

Effect of static scatterers in laser speckle contrast imaging: an experimental study on correlation and contrast

et al. 2017

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Laser speckle contrast imaging (LSCI) is a non-invasive microvascular blood flow assessment technique with good temporal and spatial resolution. Most LSCI systems, including commercial devices, can perform only qualitative blood flow evaluation, which is a major limitation of this technique. There are several factors that prevent the utilization of LSCI as a quantitative technique. Among these factors, we can highlight the effect of static scatterers. The goal of this work was to study the influence of differences in static and dynamic scatterer concentration on laser speckle correlation and contrast. In order to achieve this, a laser speckle prototype was developed and tested using an optical phantom with various concentrations of static and dynamic scatterers. It was found that the laser speckle correlation could be used to estimate the relative concentration of static/dynamic scatterers within a sample. Moreover, the speckle correlation proved to be independent of the dynamic scatterer velocity, which is a fundamental characteristic to be used in contrast correction.

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Blood velocity measurements using laser speckle imaging

Cited by 9 publications

References 4 publications

Multimodal Optical Imaging to Investigate Spatiotemporal Changes in Cerebrovascular Function in AUDA Treatment of Acute Ischemic Stroke

Multimodal Optical Imaging to Investigate Spatiotemporal Changes in Cerebrovascular Function in AUDA Treatment of Acute Ischemic Stroke

Laser Speckle Contrast Imaging for Monitoring Changes in Microvascular Blood Flow

Effect of static scatterers in laser speckle contrast imaging: an experimental study on correlation and contrast

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