5 research outputs found

    In vivo characterization of the optical and hemodynamic properties of the human sternocleidomastoid muscle through ultrasound-guided hybrid near-infrared spectroscopies

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    Objective. In this paper, we present a detailed in vivo characterization of the optical and hemodynamic properties of the human sternocleidomastoid muscle (SCM), obtained through ultrasound-guided near-infrared time-domain and diffuse correlation spectroscopies. Approach. A total of sixty-five subjects (forty-nine females, sixteen males) among healthy volunteers and thyroid nodule patients have been recruited for the study. Their SCM hemodynamic (oxy-, deoxy- and total hemoglobin concentrations, blood flow, blood oxygen saturation and metabolic rate of oxygen extraction) and optical properties (wavelength dependent absorption and reduced scattering coefficients) have been measured by the use of a novel hybrid device combining in a single unit time-domain near-infrared spectroscopy, diffuse correlation spectroscopy and simultaneous ultrasound imaging. Main results. We provide detailed tables of the results related to SCM baseline (i.e. muscle at rest) properties, and reveal significant differences on the measured parameters due to variables such as side of the neck, sex, age, body mass index, depth and thickness of the muscle, allowing future clinical studies to take into account such dependencies. Significance. The non-invasive monitoring of the hemodynamics and metabolism of the sternocleidomastoid muscle during respiration became a topic of increased interest partially due to the increased use of mechanical ventilation during the COVID-19 pandemic. Near-infrared diffuse optical spectroscopies were proposed as potential practical monitors of increased recruitment of SCM during respiratory distress. They can provide clinically relevant information on the degree of the patient's respiratory effort that is needed to maintain an optimal minute ventilation, with potential clinical application ranging from evaluating chronic pulmonary diseases to more acute settings, such as acute respiratory failure, or to determine the readiness to wean from invasive mechanical ventilation.</p

    The LUCA device: a multi-modal platform combining diffuse optics and ultrasound imaging for thyroid cancer screening

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    We present the LUCA device, a multi-modal platform combining eight-wavelengthnear infrared time resolved spectroscopy, sixteen-channel diffuse correlation spectroscopy and a clinical ultrasound in a single device. By simultaneously measuring the tissue hemodynamics and performing ultrasound imaging, this platform aims to tackle the low specificity and sensitivit yof the current thyroid cancer diagnosis techniques, improving the screening of thyroid nodules.Here, we show a detailed description of the device, components and modules. Furthermore,we show the device tests performed through well established protocols for phantom validation,and the performance assessment forin vivo. The characterization tests demonstrate that LUCA device is capable of performing high quality measurements, with a precision in determining invivo tissue optical and dynamic properties of better than 3%, and a reproducibility of better than10% after ultrasound-guided probe repositioning, even with low photon count-rates, making it suitable for a wide variety of clinical applications

    Liquid phantoms for near-infrared and diffuse correlation spectroscopies with tunable optical and dynamic properties

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    We present the recipe and characterization for preparing liquid phantoms that are suitable for both near-infrared spectroscopy and diffuse correlation spectroscopy. The phantoms have well-defined and tunable optical and dynamic properties, and consist of a solution of water and glycerol with fat emulsion as the scattering element. The recipe takes into account the effect of bulk refractive index changes due to the addition of glycerol, which is commonly used to alter the sample viscosity.Peer Reviewe
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