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Guy Cloutier - One of the best experts on this subject based on the ideXlab platform.

  • Pilot clinical study of quantitative ultrasound spectroscopy measurements of Erythrocyte Aggregation within superficial veins.
    Clinical hemorheology and microcirculation, 2020
    Co-Authors: Boris Chayer, Jean-françois Cailhier, Louise Allard, Zhao Qin, Laurence Roger, Francois Destrempes, Andre Y Denault, Julian Garcia-duitama, Guy Cloutier
    Abstract:

    BACKGROUND An enhanced inflammatory response is a trigger to the production of blood macromolecules involved in abnormally high levels of Erythrocyte Aggregation. OBJECTIVE This study aimed at demonstrating for the first time the clinical feasibility of a non-invasive ultrasound-based Erythrocyte Aggregation quantitative measurement method for potential application in critical care medicine. METHODS Erythrocyte Aggregation was evaluated using modeling of the backscatter coefficient with the Structure Factor Size and Attenuation Estimator (SFSAE). SFSAE spectral parameters W (packing factor) and D (mean aggregate diameter) were measured within the antebrachial vein of the forearm and tibial vein of the leg in 50 healthy participants at natural flow and reduced flow controlled by a pressurized bracelet. Blood samples were also collected to measure Erythrocyte Aggregation ex vivo with an erythroaggregometer (parameter S10). RESULTS W and Din vivo measurements were positively correlated with the ex vivoS10 index for both measurement sites and shear rates (correlations between 0.35-0.81, p 

  • pilot clinical study of quantitative ultrasound spectroscopy measurements of Erythrocyte Aggregation within superficial veins
    Clinical Hemorheology and Microcirculation, 2020
    Co-Authors: Boris Chayer, Jean-françois Cailhier, Louise Allard, Zhao Qin, Julian Garciaduitama, Laurence Roger, Francois Destrempes, Andre Y Denault, Guy Cloutier
    Abstract:

    BACKGROUND An enhanced inflammatory response is a trigger to the production of blood macromolecules involved in abnormally high levels of Erythrocyte Aggregation. OBJECTIVE This study aimed at demonstrating for the first time the clinical feasibility of a non-invasive ultrasound-based Erythrocyte Aggregation quantitative measurement method for potential application in critical care medicine. METHODS Erythrocyte Aggregation was evaluated using modeling of the backscatter coefficient with the Structure Factor Size and Attenuation Estimator (SFSAE). SFSAE spectral parameters W (packing factor) and D (mean aggregate diameter) were measured within the antebrachial vein of the forearm and tibial vein of the leg in 50 healthy participants at natural flow and reduced flow controlled by a pressurized bracelet. Blood samples were also collected to measure Erythrocyte Aggregation ex vivo with an erythroaggregometer (parameter S10). RESULTS W and Din vivo measurements were positively correlated with the ex vivoS10 index for both measurement sites and shear rates (correlations between 0.35-0.81, p < 0.05). Measurement at low shear rate was found to increase the sensitivity and reliability of this non-invasive measurement method. CONCLUSIONS We behold that the SFSAE method presents systemic measures of the Erythrocyte Aggregation level, since results on upper and lower limbs were highly correlated.

  • Quantitative Measurement of Erythrocyte Aggregation as a Systemic Inflammatory Marker by Ultrasound Imaging: A Systematic Review
    Ultrasound in medicine & biology, 2018
    Co-Authors: Prajwal Gyawali, Daniela Ziegler, Jean-françois Cailhier, André Denault, Guy Cloutier
    Abstract:

    Abstract This systematic review is aimed at answering two questions: (i) Is Erythrocyte Aggregation a useful biomarker in assessing systemic inflammation? (ii) Does quantitative ultrasound imaging provide the non-invasive option to measure Erythrocyte Aggregation in real time? The search was executed through bibliographic electronic databases CINAHL, EMB Review, EMBASE, MEDLINE, PubMed and the grey literature. The majority of studies correlated elevated Erythrocyte Aggregation with inflammatory blood markers for several pathologic states. Some studies used “Erythrocyte Aggregation” as an established marker of systemic inflammation. There were limited but promising articles regarding the use of quantitative ultrasound spectroscopy to monitor Erythrocyte Aggregation. Similarly, there were limited studies that used other ultrasound techniques to measure systemic inflammation. The quantitative measurement of Erythrocyte Aggregation has the potential to be a routine clinical marker of inflammation as it can reflect the cumulative inflammatory dynamics in vivo, is relatively simple to measure, is cost-effective and has a rapid turnaround time. Technologies like quantitative ultrasound spectroscopy that can measure Erythrocyte Aggregation non-invasively and in real time may offer the advantage of continuous monitoring of the inflammation state and, thus, may help in rapid decision making in a critical care setup.

  • Protocol for Robust In Vivo Measurements of Erythrocyte Aggregation Using Ultrasound Spectroscopy
    Ultrasound in Medicine and Biology, 2017
    Co-Authors: Julian Garcia-duitama, Boris Chayer, Damien Garcia, Yves Goussard, Guy Cloutier
    Abstract:

    Erythrocyte Aggregation is a non-specific marker of acute and chronic inflammation. Although it is usual to evaluate this phenomenon from blood samples analyzed in laboratory instruments, in vivo real-time assessment of Aggregation is possible with spectral ultrasound techniques. However, variable blood flow can affect the interpretation of acoustic measures. Therefore, flow standardization is required. Two techniques of flow standardization were evaluated with porcine and equine blood samples in Couette flow. These techniques consisted in either stopping the flow or reducing it. Then, the sensibility and repeatability of the retained method were evaluated in 11 human volunteers. We observed that stopping the flow compromised interpretation and repeatability. Conversely, maintaining a low flow provided repeatable measures and could distinguish between normal and high extents of Erythrocyte Aggregation. Agreement was observed between in vivo and ex vivo measures of the phenomenon (R 2 = 82.7%, p value < 0.0001). These results support the feasibility of assessing in vivo Erythrocyte Aggregation in humans by quantitative ultrasound means.

  • Protocol for Robust In Vivo Measurements of Erythrocyte Aggregation Using Ultrasound Spectroscopy.
    Ultrasound in medicine & biology, 2017
    Co-Authors: Julian Garcia-duitama, Boris Chayer, Damien Garcia, Yves Goussard, Guy Cloutier
    Abstract:

    Abstract Erythrocyte Aggregation is a non-specific marker of acute and chronic inflammation. Although it is usual to evaluate this phenomenon from blood samples analyzed in laboratory instruments, in vivo real-time assessment of Aggregation is possible with spectral ultrasound techniques. However, variable blood flow can affect the interpretation of acoustic measures. Therefore, flow standardization is required. Two techniques of flow standardization were evaluated with porcine and equine blood samples in Couette flow. These techniques consisted in either stopping the flow or reducing it. Then, the sensibility and repeatability of the retained method were evaluated in 11 human volunteers. We observed that stopping the flow compromised interpretation and repeatability. Conversely, maintaining a low flow provided repeatable measures and could distinguish between normal and high extents of Erythrocyte Aggregation. Agreement was observed between in vivo and ex vivo measures of the phenomenon ( R 2  = 82.7%, p value  in vivo Erythrocyte Aggregation in humans by quantitative ultrasound means.

Boris Chayer - One of the best experts on this subject based on the ideXlab platform.

  • Pilot clinical study of quantitative ultrasound spectroscopy measurements of Erythrocyte Aggregation within superficial veins.
    Clinical hemorheology and microcirculation, 2020
    Co-Authors: Boris Chayer, Jean-françois Cailhier, Louise Allard, Zhao Qin, Laurence Roger, Francois Destrempes, Andre Y Denault, Julian Garcia-duitama, Guy Cloutier
    Abstract:

    BACKGROUND An enhanced inflammatory response is a trigger to the production of blood macromolecules involved in abnormally high levels of Erythrocyte Aggregation. OBJECTIVE This study aimed at demonstrating for the first time the clinical feasibility of a non-invasive ultrasound-based Erythrocyte Aggregation quantitative measurement method for potential application in critical care medicine. METHODS Erythrocyte Aggregation was evaluated using modeling of the backscatter coefficient with the Structure Factor Size and Attenuation Estimator (SFSAE). SFSAE spectral parameters W (packing factor) and D (mean aggregate diameter) were measured within the antebrachial vein of the forearm and tibial vein of the leg in 50 healthy participants at natural flow and reduced flow controlled by a pressurized bracelet. Blood samples were also collected to measure Erythrocyte Aggregation ex vivo with an erythroaggregometer (parameter S10). RESULTS W and Din vivo measurements were positively correlated with the ex vivoS10 index for both measurement sites and shear rates (correlations between 0.35-0.81, p 

  • pilot clinical study of quantitative ultrasound spectroscopy measurements of Erythrocyte Aggregation within superficial veins
    Clinical Hemorheology and Microcirculation, 2020
    Co-Authors: Boris Chayer, Jean-françois Cailhier, Louise Allard, Zhao Qin, Julian Garciaduitama, Laurence Roger, Francois Destrempes, Andre Y Denault, Guy Cloutier
    Abstract:

    BACKGROUND An enhanced inflammatory response is a trigger to the production of blood macromolecules involved in abnormally high levels of Erythrocyte Aggregation. OBJECTIVE This study aimed at demonstrating for the first time the clinical feasibility of a non-invasive ultrasound-based Erythrocyte Aggregation quantitative measurement method for potential application in critical care medicine. METHODS Erythrocyte Aggregation was evaluated using modeling of the backscatter coefficient with the Structure Factor Size and Attenuation Estimator (SFSAE). SFSAE spectral parameters W (packing factor) and D (mean aggregate diameter) were measured within the antebrachial vein of the forearm and tibial vein of the leg in 50 healthy participants at natural flow and reduced flow controlled by a pressurized bracelet. Blood samples were also collected to measure Erythrocyte Aggregation ex vivo with an erythroaggregometer (parameter S10). RESULTS W and Din vivo measurements were positively correlated with the ex vivoS10 index for both measurement sites and shear rates (correlations between 0.35-0.81, p < 0.05). Measurement at low shear rate was found to increase the sensitivity and reliability of this non-invasive measurement method. CONCLUSIONS We behold that the SFSAE method presents systemic measures of the Erythrocyte Aggregation level, since results on upper and lower limbs were highly correlated.

  • Protocol for Robust In Vivo Measurements of Erythrocyte Aggregation Using Ultrasound Spectroscopy
    Ultrasound in Medicine and Biology, 2017
    Co-Authors: Julian Garcia-duitama, Boris Chayer, Damien Garcia, Yves Goussard, Guy Cloutier
    Abstract:

    Erythrocyte Aggregation is a non-specific marker of acute and chronic inflammation. Although it is usual to evaluate this phenomenon from blood samples analyzed in laboratory instruments, in vivo real-time assessment of Aggregation is possible with spectral ultrasound techniques. However, variable blood flow can affect the interpretation of acoustic measures. Therefore, flow standardization is required. Two techniques of flow standardization were evaluated with porcine and equine blood samples in Couette flow. These techniques consisted in either stopping the flow or reducing it. Then, the sensibility and repeatability of the retained method were evaluated in 11 human volunteers. We observed that stopping the flow compromised interpretation and repeatability. Conversely, maintaining a low flow provided repeatable measures and could distinguish between normal and high extents of Erythrocyte Aggregation. Agreement was observed between in vivo and ex vivo measures of the phenomenon (R 2 = 82.7%, p value < 0.0001). These results support the feasibility of assessing in vivo Erythrocyte Aggregation in humans by quantitative ultrasound means.

  • Protocol for Robust In Vivo Measurements of Erythrocyte Aggregation Using Ultrasound Spectroscopy.
    Ultrasound in medicine & biology, 2017
    Co-Authors: Julian Garcia-duitama, Boris Chayer, Damien Garcia, Yves Goussard, Guy Cloutier
    Abstract:

    Abstract Erythrocyte Aggregation is a non-specific marker of acute and chronic inflammation. Although it is usual to evaluate this phenomenon from blood samples analyzed in laboratory instruments, in vivo real-time assessment of Aggregation is possible with spectral ultrasound techniques. However, variable blood flow can affect the interpretation of acoustic measures. Therefore, flow standardization is required. Two techniques of flow standardization were evaluated with porcine and equine blood samples in Couette flow. These techniques consisted in either stopping the flow or reducing it. Then, the sensibility and repeatability of the retained method were evaluated in 11 human volunteers. We observed that stopping the flow compromised interpretation and repeatability. Conversely, maintaining a low flow provided repeatable measures and could distinguish between normal and high extents of Erythrocyte Aggregation. Agreement was observed between in vivo and ex vivo measures of the phenomenon ( R 2  = 82.7%, p value  in vivo Erythrocyte Aggregation in humans by quantitative ultrasound means.

Julian Garcia-duitama - One of the best experts on this subject based on the ideXlab platform.

  • Pilot clinical study of quantitative ultrasound spectroscopy measurements of Erythrocyte Aggregation within superficial veins.
    Clinical hemorheology and microcirculation, 2020
    Co-Authors: Boris Chayer, Jean-françois Cailhier, Louise Allard, Zhao Qin, Laurence Roger, Francois Destrempes, Andre Y Denault, Julian Garcia-duitama, Guy Cloutier
    Abstract:

    BACKGROUND An enhanced inflammatory response is a trigger to the production of blood macromolecules involved in abnormally high levels of Erythrocyte Aggregation. OBJECTIVE This study aimed at demonstrating for the first time the clinical feasibility of a non-invasive ultrasound-based Erythrocyte Aggregation quantitative measurement method for potential application in critical care medicine. METHODS Erythrocyte Aggregation was evaluated using modeling of the backscatter coefficient with the Structure Factor Size and Attenuation Estimator (SFSAE). SFSAE spectral parameters W (packing factor) and D (mean aggregate diameter) were measured within the antebrachial vein of the forearm and tibial vein of the leg in 50 healthy participants at natural flow and reduced flow controlled by a pressurized bracelet. Blood samples were also collected to measure Erythrocyte Aggregation ex vivo with an erythroaggregometer (parameter S10). RESULTS W and Din vivo measurements were positively correlated with the ex vivoS10 index for both measurement sites and shear rates (correlations between 0.35-0.81, p 

  • Protocol for Robust In Vivo Measurements of Erythrocyte Aggregation Using Ultrasound Spectroscopy
    Ultrasound in Medicine and Biology, 2017
    Co-Authors: Julian Garcia-duitama, Boris Chayer, Damien Garcia, Yves Goussard, Guy Cloutier
    Abstract:

    Erythrocyte Aggregation is a non-specific marker of acute and chronic inflammation. Although it is usual to evaluate this phenomenon from blood samples analyzed in laboratory instruments, in vivo real-time assessment of Aggregation is possible with spectral ultrasound techniques. However, variable blood flow can affect the interpretation of acoustic measures. Therefore, flow standardization is required. Two techniques of flow standardization were evaluated with porcine and equine blood samples in Couette flow. These techniques consisted in either stopping the flow or reducing it. Then, the sensibility and repeatability of the retained method were evaluated in 11 human volunteers. We observed that stopping the flow compromised interpretation and repeatability. Conversely, maintaining a low flow provided repeatable measures and could distinguish between normal and high extents of Erythrocyte Aggregation. Agreement was observed between in vivo and ex vivo measures of the phenomenon (R 2 = 82.7%, p value < 0.0001). These results support the feasibility of assessing in vivo Erythrocyte Aggregation in humans by quantitative ultrasound means.

  • Protocol for Robust In Vivo Measurements of Erythrocyte Aggregation Using Ultrasound Spectroscopy.
    Ultrasound in medicine & biology, 2017
    Co-Authors: Julian Garcia-duitama, Boris Chayer, Damien Garcia, Yves Goussard, Guy Cloutier
    Abstract:

    Abstract Erythrocyte Aggregation is a non-specific marker of acute and chronic inflammation. Although it is usual to evaluate this phenomenon from blood samples analyzed in laboratory instruments, in vivo real-time assessment of Aggregation is possible with spectral ultrasound techniques. However, variable blood flow can affect the interpretation of acoustic measures. Therefore, flow standardization is required. Two techniques of flow standardization were evaluated with porcine and equine blood samples in Couette flow. These techniques consisted in either stopping the flow or reducing it. Then, the sensibility and repeatability of the retained method were evaluated in 11 human volunteers. We observed that stopping the flow compromised interpretation and repeatability. Conversely, maintaining a low flow provided repeatable measures and could distinguish between normal and high extents of Erythrocyte Aggregation. Agreement was observed between in vivo and ex vivo measures of the phenomenon ( R 2  = 82.7%, p value  in vivo Erythrocyte Aggregation in humans by quantitative ultrasound means.

Jean-françois Cailhier - One of the best experts on this subject based on the ideXlab platform.

  • Pilot clinical study of quantitative ultrasound spectroscopy measurements of Erythrocyte Aggregation within superficial veins.
    Clinical hemorheology and microcirculation, 2020
    Co-Authors: Boris Chayer, Jean-françois Cailhier, Louise Allard, Zhao Qin, Laurence Roger, Francois Destrempes, Andre Y Denault, Julian Garcia-duitama, Guy Cloutier
    Abstract:

    BACKGROUND An enhanced inflammatory response is a trigger to the production of blood macromolecules involved in abnormally high levels of Erythrocyte Aggregation. OBJECTIVE This study aimed at demonstrating for the first time the clinical feasibility of a non-invasive ultrasound-based Erythrocyte Aggregation quantitative measurement method for potential application in critical care medicine. METHODS Erythrocyte Aggregation was evaluated using modeling of the backscatter coefficient with the Structure Factor Size and Attenuation Estimator (SFSAE). SFSAE spectral parameters W (packing factor) and D (mean aggregate diameter) were measured within the antebrachial vein of the forearm and tibial vein of the leg in 50 healthy participants at natural flow and reduced flow controlled by a pressurized bracelet. Blood samples were also collected to measure Erythrocyte Aggregation ex vivo with an erythroaggregometer (parameter S10). RESULTS W and Din vivo measurements were positively correlated with the ex vivoS10 index for both measurement sites and shear rates (correlations between 0.35-0.81, p 

  • pilot clinical study of quantitative ultrasound spectroscopy measurements of Erythrocyte Aggregation within superficial veins
    Clinical Hemorheology and Microcirculation, 2020
    Co-Authors: Boris Chayer, Jean-françois Cailhier, Louise Allard, Zhao Qin, Julian Garciaduitama, Laurence Roger, Francois Destrempes, Andre Y Denault, Guy Cloutier
    Abstract:

    BACKGROUND An enhanced inflammatory response is a trigger to the production of blood macromolecules involved in abnormally high levels of Erythrocyte Aggregation. OBJECTIVE This study aimed at demonstrating for the first time the clinical feasibility of a non-invasive ultrasound-based Erythrocyte Aggregation quantitative measurement method for potential application in critical care medicine. METHODS Erythrocyte Aggregation was evaluated using modeling of the backscatter coefficient with the Structure Factor Size and Attenuation Estimator (SFSAE). SFSAE spectral parameters W (packing factor) and D (mean aggregate diameter) were measured within the antebrachial vein of the forearm and tibial vein of the leg in 50 healthy participants at natural flow and reduced flow controlled by a pressurized bracelet. Blood samples were also collected to measure Erythrocyte Aggregation ex vivo with an erythroaggregometer (parameter S10). RESULTS W and Din vivo measurements were positively correlated with the ex vivoS10 index for both measurement sites and shear rates (correlations between 0.35-0.81, p < 0.05). Measurement at low shear rate was found to increase the sensitivity and reliability of this non-invasive measurement method. CONCLUSIONS We behold that the SFSAE method presents systemic measures of the Erythrocyte Aggregation level, since results on upper and lower limbs were highly correlated.

  • Quantitative Measurement of Erythrocyte Aggregation as a Systemic Inflammatory Marker by Ultrasound Imaging: A Systematic Review
    Ultrasound in medicine & biology, 2018
    Co-Authors: Prajwal Gyawali, Daniela Ziegler, Jean-françois Cailhier, André Denault, Guy Cloutier
    Abstract:

    Abstract This systematic review is aimed at answering two questions: (i) Is Erythrocyte Aggregation a useful biomarker in assessing systemic inflammation? (ii) Does quantitative ultrasound imaging provide the non-invasive option to measure Erythrocyte Aggregation in real time? The search was executed through bibliographic electronic databases CINAHL, EMB Review, EMBASE, MEDLINE, PubMed and the grey literature. The majority of studies correlated elevated Erythrocyte Aggregation with inflammatory blood markers for several pathologic states. Some studies used “Erythrocyte Aggregation” as an established marker of systemic inflammation. There were limited but promising articles regarding the use of quantitative ultrasound spectroscopy to monitor Erythrocyte Aggregation. Similarly, there were limited studies that used other ultrasound techniques to measure systemic inflammation. The quantitative measurement of Erythrocyte Aggregation has the potential to be a routine clinical marker of inflammation as it can reflect the cumulative inflammatory dynamics in vivo, is relatively simple to measure, is cost-effective and has a rapid turnaround time. Technologies like quantitative ultrasound spectroscopy that can measure Erythrocyte Aggregation non-invasively and in real time may offer the advantage of continuous monitoring of the inflammation state and, thus, may help in rapid decision making in a critical care setup.

Gabriel Coscas - One of the best experts on this subject based on the ideXlab platform.

  • Elevated Erythrocyte Aggregation in Patients with Central Retinal Vein Occlusion and without Conventional Risk Factors
    Ophthalmology, 1994
    Co-Authors: A. Glacet-bernard, A. Chabanel, F. Lelong, M. Samama, Gabriel Coscas
    Abstract:

    Background: Retinal venous circulation is characterized by the combination of a low flow state and a high vascular resistance, which would make it particularly dependent on blood viscosity. Erythrocyte Aggregation is the chief determinant of blood viscosity at low shear rates. Recent studies have demonstrated increased Erythrocyte Aggregation in many systemic vascular disorders and also in retinal vein occlusion. Methods: To assess the possible role of abnormal hemorheologic findings in the pathogenesis of central retinal vein occlusion (CRVO), the authors retrospectively studied Erythrocyte Aggregation and hematocrit and fibrinogen levels in 33 patients with CRVO and without any known risk factors (diabetes, hypertension, smoking, hyperlipidemia, cardiovascular disease, glaucoma). Erythrocyte Aggregation was assessed with a light back-scattering method. Results were compared with those of a group of 33 age- and sex-matched controls. Results: Eleven (33%) of the 33 patients with CRVO had abnormal hemorheologic findings. Erythrocyte Aggregation was highly significantly increased in the CRVO group when compared with the control group ( P P Conclusion: These data suggest that abnormal hemorheologic findings could affect the pathogenesis of CRVO, and perhaps be predictive of an aggravation. The latter hypothesis needs to be confirmed in a larger, prospective study.