The Experts below are selected from a list of 261 Experts worldwide ranked by ideXlab platform
Leo K Cheng - One of the best experts on this subject based on the ideXlab platform.
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high resolution electrical mapping of porcine gastric slow wave propagation from the Mucosal Surface
Neurogastroenterology and Motility, 2017Co-Authors: Timothy R Angeli, Peng Du, Niranchan Paskaranandavadivel, Shameer Sathar, A Hall, Samuel J Asirvatham, Gianrico Farrugia, John A Windsor, Leo K ChengAbstract:BACKGROUND: Gastric motility is coordinated by bioelectrical slow waves, and gastric dysrhythmias are reported in motility disorders. High-resolution (HR) mapping has advanced the accurate assessment of gastric dysrhythmias, offering promise as a diagnostic technique. However, HR mapping has been restricted to invasive surgical serosal access. This study investigates the feasibility of HR mapping from the gastric Mucosal Surface. METHODS: Experiments were conducted in vivo in 14 weaner pigs. Reference serosal recordings were performed with flexible-printed-circuit (FPC) arrays (128-192 electrodes). Mucosal recordings were performed by two methods: (i) FPC array aligned directly opposite the serosal array, and (ii) cardiac mapping catheter modified for gastric Mucosal recordings. Slow-wave propagation and morphology characteristics were quantified and compared between simultaneous serosal and Mucosal recordings. KEY RESULTS: Slow-wave activity was consistently recorded from the Mucosal Surface from both electrode arrays. Mucosally recorded slow-wave propagation was consistent with reference serosal activation pattern, frequency (P≥.3), and velocity (P≥.4). However, Mucosally recorded slow-wave morphology exhibited reduced amplitude (65-72% reduced, P<.001) and wider downstroke width (18-31% wider, P≤.02), compared to serosal data. Dysrhythmias were successfully mapped and classified from the Mucosal Surface, accorded with serosal data, and were consistent with known dysrhythmic mechanisms in the porcine model. CONCLUSIONS & INFERENCES: High-resolution gastric electrical mapping was achieved from the Mucosal Surface, and demonstrated consistent propagation characteristics with serosal data. However, Mucosal signal morphology was attenuated, demonstrating necessity for optimized electrode designs and analytical algorithms. This study demonstrates feasibility of endoscopic HR mapping, providing a foundation for advancement of minimally invasive spatiotemporal gastric mapping as a clinical and scientific tool.
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High-resolution electrical mapping of porcine gastric slow-wave propagation from the Mucosal Surface.
Neurogastroenterology and Motility, 2016Co-Authors: Timothy R Angeli, Peng Du, Niranchan Paskaranandavadivel, Shameer Sathar, A Hall, Samuel J Asirvatham, Gianrico Farrugia, John A Windsor, Leo K Cheng, Gregory O'gradyAbstract:BACKGROUND: Gastric motility is coordinated by bioelectrical slow waves, and gastric dysrhythmias are reported in motility disorders. High-resolution (HR) mapping has advanced the accurate assessment of gastric dysrhythmias, offering promise as a diagnostic technique. However, HR mapping has been restricted to invasive surgical serosal access. This study investigates the feasibility of HR mapping from the gastric Mucosal Surface. METHODS: Experiments were conducted in vivo in 14 weaner pigs. Reference serosal recordings were performed with flexible-printed-circuit (FPC) arrays (128-192 electrodes). Mucosal recordings were performed by two methods: (i) FPC array aligned directly opposite the serosal array, and (ii) cardiac mapping catheter modified for gastric Mucosal recordings. Slow-wave propagation and morphology characteristics were quantified and compared between simultaneous serosal and Mucosal recordings. KEY RESULTS: Slow-wave activity was consistently recorded from the Mucosal Surface from both electrode arrays. Mucosally recorded slow-wave propagation was consistent with reference serosal activation pattern, frequency (P≥.3), and velocity (P≥.4). However, Mucosally recorded slow-wave morphology exhibited reduced amplitude (65-72% reduced, P
Kristina Kairaitis - One of the best experts on this subject based on the ideXlab platform.
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modelling Mucosal Surface roughness in the human velopharynx a computational fluid dynamics study of healthy and obstructive sleep apnea airways
Journal of Applied Physiology, 2018Co-Authors: Christopher Lambeth, Ziyu Wang, Kristina Kairaitis, Abouzar Moshfegh, Ahmad Jabbarzadeh, Terence C. AmisAbstract:Increased Mucosal Surface roughness in the velopharynx of patients with obstructive sleep apnea (OSA) has recently been identified, but its role in OSA pathogenesis is unknown. This is the first st...
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velopharyngeal Mucosal Surface topography in healthy subjects and subjects with obstructive sleep apnea
Journal of Applied Physiology, 2017Co-Authors: Christopher Lambeth, Jason Amatoury, Ziyu Wang, Sheryl Foster, Terence C. Amis, Kristina KairaitisAbstract:A new methodology was used to model the upper airway Mucosal Surface topography from magnetic resonance images of patients with obstructive sleep apnea and healthy adults. Curvature analysis was us...
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Velopharyngeal Mucosal Surface topography in healthy subjects and subjects with obstructive sleep apnea
Journal of Applied Physiology, 2016Co-Authors: Christopher Lambeth, Jason Amatoury, Ziyu Wang, Sheryl Foster, Terence C. Amis, Kristina KairaitisAbstract:Macroscopic pharyngeal anatomical abnormalities are thought to contribute to the pathogenesis of upper airway (UA) obstruction in obstructive sleep apnea (OSA). Microscopic changes in the UA Mucosal lining of OSA subjects are reported; however, the impact of these changes on UA Mucosal Surface topography is unknown. This study aimed to 1 ) develop methodology to measure UA Mucosal Surface topography, and 2 ) compare findings from healthy and OSA subjects. Ten healthy and eleven OSA subjects were studied. Awake, gated (end expiration), head and neck position controlled magnetic resonance images (MRIs) of the velopharynx (VP) were obtained. VP Mucosal Surfaces were segmented from axial images, and three-dimensional VP Mucosal Surface models were constructed. Curvature analysis of the models was used to study the VP Mucosal Surface topography. Principal, mean, and Gaussian curvatures were used to define Surface shape composition and Surface roughness of the VP Mucosal Surface models. Significant differences were found in the Surface shape composition, with more saddle/spherical and less flat/cylindrical shapes in OSA than healthy VP Mucosal Surface models ( P < 0.01). OSA VP Mucosal Surface models were also found to have more Mucosal Surface roughness ( P < 0.0001) than healthy VP Mucosal Surface models. Our novel methodology was utilized to model the VP Mucosal Surface of OSA and healthy subjects. OSA subjects were found to have different VP Mucosal Surface topography, composed of increased irregular shapes and increased roughness. We speculate increased irregularity in VP Mucosal Surface may increase pharyngeal collapsibility as a consequence of friction-related pressure loss. NEW & NOTEWORTHY A new methodology was used to model the upper airway Mucosal Surface topography from magnetic resonance images of patients with obstructive sleep apnea and healthy adults. Curvature analysis was used to analyze the topography of the models, and a new metric was derived to describe the Mucosal Surface roughness. Increased roughness was found in the obstructive sleep apnea vs. healthy group, but further research is required to determine the functional effects of the measured difference on upper airway airflow mechanics.
Terence C. Amis - One of the best experts on this subject based on the ideXlab platform.
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modelling Mucosal Surface roughness in the human velopharynx a computational fluid dynamics study of healthy and obstructive sleep apnea airways
Journal of Applied Physiology, 2018Co-Authors: Christopher Lambeth, Ziyu Wang, Kristina Kairaitis, Abouzar Moshfegh, Ahmad Jabbarzadeh, Terence C. AmisAbstract:Increased Mucosal Surface roughness in the velopharynx of patients with obstructive sleep apnea (OSA) has recently been identified, but its role in OSA pathogenesis is unknown. This is the first st...
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velopharyngeal Mucosal Surface topography in healthy subjects and subjects with obstructive sleep apnea
Journal of Applied Physiology, 2017Co-Authors: Christopher Lambeth, Jason Amatoury, Ziyu Wang, Sheryl Foster, Terence C. Amis, Kristina KairaitisAbstract:A new methodology was used to model the upper airway Mucosal Surface topography from magnetic resonance images of patients with obstructive sleep apnea and healthy adults. Curvature analysis was us...
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Velopharyngeal Mucosal Surface topography in healthy subjects and subjects with obstructive sleep apnea
Journal of Applied Physiology, 2016Co-Authors: Christopher Lambeth, Jason Amatoury, Ziyu Wang, Sheryl Foster, Terence C. Amis, Kristina KairaitisAbstract:Macroscopic pharyngeal anatomical abnormalities are thought to contribute to the pathogenesis of upper airway (UA) obstruction in obstructive sleep apnea (OSA). Microscopic changes in the UA Mucosal lining of OSA subjects are reported; however, the impact of these changes on UA Mucosal Surface topography is unknown. This study aimed to 1 ) develop methodology to measure UA Mucosal Surface topography, and 2 ) compare findings from healthy and OSA subjects. Ten healthy and eleven OSA subjects were studied. Awake, gated (end expiration), head and neck position controlled magnetic resonance images (MRIs) of the velopharynx (VP) were obtained. VP Mucosal Surfaces were segmented from axial images, and three-dimensional VP Mucosal Surface models were constructed. Curvature analysis of the models was used to study the VP Mucosal Surface topography. Principal, mean, and Gaussian curvatures were used to define Surface shape composition and Surface roughness of the VP Mucosal Surface models. Significant differences were found in the Surface shape composition, with more saddle/spherical and less flat/cylindrical shapes in OSA than healthy VP Mucosal Surface models ( P < 0.01). OSA VP Mucosal Surface models were also found to have more Mucosal Surface roughness ( P < 0.0001) than healthy VP Mucosal Surface models. Our novel methodology was utilized to model the VP Mucosal Surface of OSA and healthy subjects. OSA subjects were found to have different VP Mucosal Surface topography, composed of increased irregular shapes and increased roughness. We speculate increased irregularity in VP Mucosal Surface may increase pharyngeal collapsibility as a consequence of friction-related pressure loss. NEW & NOTEWORTHY A new methodology was used to model the upper airway Mucosal Surface topography from magnetic resonance images of patients with obstructive sleep apnea and healthy adults. Curvature analysis was used to analyze the topography of the models, and a new metric was derived to describe the Mucosal Surface roughness. Increased roughness was found in the obstructive sleep apnea vs. healthy group, but further research is required to determine the functional effects of the measured difference on upper airway airflow mechanics.
Christopher Lambeth - One of the best experts on this subject based on the ideXlab platform.
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modelling Mucosal Surface roughness in the human velopharynx a computational fluid dynamics study of healthy and obstructive sleep apnea airways
Journal of Applied Physiology, 2018Co-Authors: Christopher Lambeth, Ziyu Wang, Kristina Kairaitis, Abouzar Moshfegh, Ahmad Jabbarzadeh, Terence C. AmisAbstract:Increased Mucosal Surface roughness in the velopharynx of patients with obstructive sleep apnea (OSA) has recently been identified, but its role in OSA pathogenesis is unknown. This is the first st...
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velopharyngeal Mucosal Surface topography in healthy subjects and subjects with obstructive sleep apnea
Journal of Applied Physiology, 2017Co-Authors: Christopher Lambeth, Jason Amatoury, Ziyu Wang, Sheryl Foster, Terence C. Amis, Kristina KairaitisAbstract:A new methodology was used to model the upper airway Mucosal Surface topography from magnetic resonance images of patients with obstructive sleep apnea and healthy adults. Curvature analysis was us...
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Velopharyngeal Mucosal Surface topography in healthy subjects and subjects with obstructive sleep apnea
Journal of Applied Physiology, 2016Co-Authors: Christopher Lambeth, Jason Amatoury, Ziyu Wang, Sheryl Foster, Terence C. Amis, Kristina KairaitisAbstract:Macroscopic pharyngeal anatomical abnormalities are thought to contribute to the pathogenesis of upper airway (UA) obstruction in obstructive sleep apnea (OSA). Microscopic changes in the UA Mucosal lining of OSA subjects are reported; however, the impact of these changes on UA Mucosal Surface topography is unknown. This study aimed to 1 ) develop methodology to measure UA Mucosal Surface topography, and 2 ) compare findings from healthy and OSA subjects. Ten healthy and eleven OSA subjects were studied. Awake, gated (end expiration), head and neck position controlled magnetic resonance images (MRIs) of the velopharynx (VP) were obtained. VP Mucosal Surfaces were segmented from axial images, and three-dimensional VP Mucosal Surface models were constructed. Curvature analysis of the models was used to study the VP Mucosal Surface topography. Principal, mean, and Gaussian curvatures were used to define Surface shape composition and Surface roughness of the VP Mucosal Surface models. Significant differences were found in the Surface shape composition, with more saddle/spherical and less flat/cylindrical shapes in OSA than healthy VP Mucosal Surface models ( P < 0.01). OSA VP Mucosal Surface models were also found to have more Mucosal Surface roughness ( P < 0.0001) than healthy VP Mucosal Surface models. Our novel methodology was utilized to model the VP Mucosal Surface of OSA and healthy subjects. OSA subjects were found to have different VP Mucosal Surface topography, composed of increased irregular shapes and increased roughness. We speculate increased irregularity in VP Mucosal Surface may increase pharyngeal collapsibility as a consequence of friction-related pressure loss. NEW & NOTEWORTHY A new methodology was used to model the upper airway Mucosal Surface topography from magnetic resonance images of patients with obstructive sleep apnea and healthy adults. Curvature analysis was used to analyze the topography of the models, and a new metric was derived to describe the Mucosal Surface roughness. Increased roughness was found in the obstructive sleep apnea vs. healthy group, but further research is required to determine the functional effects of the measured difference on upper airway airflow mechanics.
Ziyu Wang - One of the best experts on this subject based on the ideXlab platform.
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modelling Mucosal Surface roughness in the human velopharynx a computational fluid dynamics study of healthy and obstructive sleep apnea airways
Journal of Applied Physiology, 2018Co-Authors: Christopher Lambeth, Ziyu Wang, Kristina Kairaitis, Abouzar Moshfegh, Ahmad Jabbarzadeh, Terence C. AmisAbstract:Increased Mucosal Surface roughness in the velopharynx of patients with obstructive sleep apnea (OSA) has recently been identified, but its role in OSA pathogenesis is unknown. This is the first st...
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velopharyngeal Mucosal Surface topography in healthy subjects and subjects with obstructive sleep apnea
Journal of Applied Physiology, 2017Co-Authors: Christopher Lambeth, Jason Amatoury, Ziyu Wang, Sheryl Foster, Terence C. Amis, Kristina KairaitisAbstract:A new methodology was used to model the upper airway Mucosal Surface topography from magnetic resonance images of patients with obstructive sleep apnea and healthy adults. Curvature analysis was us...
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Velopharyngeal Mucosal Surface topography in healthy subjects and subjects with obstructive sleep apnea
Journal of Applied Physiology, 2016Co-Authors: Christopher Lambeth, Jason Amatoury, Ziyu Wang, Sheryl Foster, Terence C. Amis, Kristina KairaitisAbstract:Macroscopic pharyngeal anatomical abnormalities are thought to contribute to the pathogenesis of upper airway (UA) obstruction in obstructive sleep apnea (OSA). Microscopic changes in the UA Mucosal lining of OSA subjects are reported; however, the impact of these changes on UA Mucosal Surface topography is unknown. This study aimed to 1 ) develop methodology to measure UA Mucosal Surface topography, and 2 ) compare findings from healthy and OSA subjects. Ten healthy and eleven OSA subjects were studied. Awake, gated (end expiration), head and neck position controlled magnetic resonance images (MRIs) of the velopharynx (VP) were obtained. VP Mucosal Surfaces were segmented from axial images, and three-dimensional VP Mucosal Surface models were constructed. Curvature analysis of the models was used to study the VP Mucosal Surface topography. Principal, mean, and Gaussian curvatures were used to define Surface shape composition and Surface roughness of the VP Mucosal Surface models. Significant differences were found in the Surface shape composition, with more saddle/spherical and less flat/cylindrical shapes in OSA than healthy VP Mucosal Surface models ( P < 0.01). OSA VP Mucosal Surface models were also found to have more Mucosal Surface roughness ( P < 0.0001) than healthy VP Mucosal Surface models. Our novel methodology was utilized to model the VP Mucosal Surface of OSA and healthy subjects. OSA subjects were found to have different VP Mucosal Surface topography, composed of increased irregular shapes and increased roughness. We speculate increased irregularity in VP Mucosal Surface may increase pharyngeal collapsibility as a consequence of friction-related pressure loss. NEW & NOTEWORTHY A new methodology was used to model the upper airway Mucosal Surface topography from magnetic resonance images of patients with obstructive sleep apnea and healthy adults. Curvature analysis was used to analyze the topography of the models, and a new metric was derived to describe the Mucosal Surface roughness. Increased roughness was found in the obstructive sleep apnea vs. healthy group, but further research is required to determine the functional effects of the measured difference on upper airway airflow mechanics.