The Experts below are selected from a list of 81177 Experts worldwide ranked by ideXlab platform
Michal Byra - One of the best experts on this subject based on the ideXlab platform.
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quantitative ultrasound and b Mode Image texture features correlate with collagen and myelin content in human ulnar nerve fascicles
Ultrasound in Medicine and Biology, 2019Co-Authors: Michal Byra, Lidi Wan, Jonathan Wong, Sameer B Shah, Michael P Andre, Eric Y ChangAbstract:We investigate the usefulness of quantitative ultrasound and B-Mode texture features for characterization of ulnar nerve fascicles. Ultrasound data were acquired from cadaveric specimens using a nominal 30-MHz probe. Next, the nerves were extracted to prepare histology sections. Eighty-five fascicles were matched between the B-Mode Images and the histology sections. For each fascicle Image, we selected an intra-fascicular region of interest. We used histology sections to determine features related to the concentration of collagen and myelin and ultrasound data to calculate the backscatter coefficient (-24.89 ± 8.31 dB), attenuation coefficient (0.92 ± 0.04 db/cm-MHz), Nakagami parameter (1.01 ± 0.18) and entropy (6.92 ± 0.83), as well as B-Mode texture features obtained via the gray-level co-occurrence matrix algorithm. Significant Spearman rank correlations between the combined collagen and myelin concentrations were obtained for the backscatter coefficient (R = -0.68), entropy (R = -0.51) and several texture features. Our study indicates that quantitative ultrasound may potentially provide information on structural components of nerve fascicles.
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quantitative ultrasound and b Mode Image texture features correlate with collagen and myelin content in human ulnar nerve fascicles
arXiv: Medical Physics, 2019Co-Authors: Michal Byra, Lidi Wan, Jonathan Wong, Sameer B Shah, Michael P Andre, Eric Y ChangAbstract:We investigate the usefulness of quantitative ultrasound (QUS) and B-Mode texture features for characterization of ulnar nerve fascicles. Ultrasound data were acquired from cadaveric specimens using a nominal 30 MHz probe. Next, the nerves were extracted to prepare histology sections. 85 fascicles were matched between the B-Mode Images and the histology sections. For each fascicle Image, we selected an intra-fascicular region of interest. We used histology sections to determine features related to the concentration of collagen and myelin, and ultrasound data to calculate backscatter coefficient (-24.89 dB $\pm$ 8.31), attenuation coefficient (0.92 db/cm-MHz $\pm$ 0.04), Nakagami parameter (1.01 $\pm$ 0.18) and entropy (6.92 $\pm$ 0.83), as well as B-Mode texture features obtained via the gray level co-occurrence matrix algorithm. Significant Spearman's rank correlations between the combined collagen and myelin concentrations were obtained for the backscatter coefficient (R=-0.68), entropy (R=-0.51), and for several texture features. Our study demonstrates that QUS may potentially provide information on structural components of nerve fascicles.
Eric Y Chang - One of the best experts on this subject based on the ideXlab platform.
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quantitative ultrasound and b Mode Image texture features correlate with collagen and myelin content in human ulnar nerve fascicles
Ultrasound in Medicine and Biology, 2019Co-Authors: Michal Byra, Lidi Wan, Jonathan Wong, Sameer B Shah, Michael P Andre, Eric Y ChangAbstract:We investigate the usefulness of quantitative ultrasound and B-Mode texture features for characterization of ulnar nerve fascicles. Ultrasound data were acquired from cadaveric specimens using a nominal 30-MHz probe. Next, the nerves were extracted to prepare histology sections. Eighty-five fascicles were matched between the B-Mode Images and the histology sections. For each fascicle Image, we selected an intra-fascicular region of interest. We used histology sections to determine features related to the concentration of collagen and myelin and ultrasound data to calculate the backscatter coefficient (-24.89 ± 8.31 dB), attenuation coefficient (0.92 ± 0.04 db/cm-MHz), Nakagami parameter (1.01 ± 0.18) and entropy (6.92 ± 0.83), as well as B-Mode texture features obtained via the gray-level co-occurrence matrix algorithm. Significant Spearman rank correlations between the combined collagen and myelin concentrations were obtained for the backscatter coefficient (R = -0.68), entropy (R = -0.51) and several texture features. Our study indicates that quantitative ultrasound may potentially provide information on structural components of nerve fascicles.
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quantitative ultrasound and b Mode Image texture features correlate with collagen and myelin content in human ulnar nerve fascicles
arXiv: Medical Physics, 2019Co-Authors: Michal Byra, Lidi Wan, Jonathan Wong, Sameer B Shah, Michael P Andre, Eric Y ChangAbstract:We investigate the usefulness of quantitative ultrasound (QUS) and B-Mode texture features for characterization of ulnar nerve fascicles. Ultrasound data were acquired from cadaveric specimens using a nominal 30 MHz probe. Next, the nerves were extracted to prepare histology sections. 85 fascicles were matched between the B-Mode Images and the histology sections. For each fascicle Image, we selected an intra-fascicular region of interest. We used histology sections to determine features related to the concentration of collagen and myelin, and ultrasound data to calculate backscatter coefficient (-24.89 dB $\pm$ 8.31), attenuation coefficient (0.92 db/cm-MHz $\pm$ 0.04), Nakagami parameter (1.01 $\pm$ 0.18) and entropy (6.92 $\pm$ 0.83), as well as B-Mode texture features obtained via the gray level co-occurrence matrix algorithm. Significant Spearman's rank correlations between the combined collagen and myelin concentrations were obtained for the backscatter coefficient (R=-0.68), entropy (R=-0.51), and for several texture features. Our study demonstrates that QUS may potentially provide information on structural components of nerve fascicles.
Haitao Chen - One of the best experts on this subject based on the ideXlab platform.
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measurement of radial elasticity and original height of dna duplex using tapping Mode atomic force microscopy
Nanomaterials, 2019Co-Authors: Longhai Li, Xu Zhang, Hongfei Wang, Qian Lang, Haitao ChenAbstract:Atomic force microscopy (AFM) can characterize nanomaterial elasticity. However, some one-dimensional nanomaterials, such as DNA, are too small to locate with an AFM tip because of thermal drift and the nonlinearity of piezoelectric actuators. In this study, we propose a novel approach to address the shortcomings of AFM and obtain the radial Young’s modulus of a DNA duplex. The elastic properties are evaluated by combining physical calculations and measured experimental results. The initial elasticity of the DNA is first assumed; based on tapping-Mode scanning Images and tip–sample interaction force simulations, the calculated elastic modulus is extracted. By minimizing the error between the assumed and experimental values, the extracted elasticity is assigned as the actual modulus for the material. Furthermore, tapping-Mode Image scanning avoids the necessity of locating the probe exactly on the target sample. In addition to elasticity measurements, the deformation caused by the tapping force from the AFM tip is compensated and the original height of the DNA is calculated. The results show that the radial compressive Young’s modulus of DNA is 125–150 MPa under a tapping force of 0.5–1.3 nN; its original height is 1.9 nm. This approach can be applied to the measurement of other nanomaterials.
Stephen C. Minne - One of the best experts on this subject based on the ideXlab platform.
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self sensing tapping Mode atomic force microscopy
Sensors and Actuators A-physical, 2005Co-Authors: Jesse Adams, B. Rogers, L. Manning, M. Jones, Stephen C. MinneAbstract:We demonstrate self-sensing tapping Mode using commercially available, low-stress, piezoelectric cantilevers with sharp, integrated, silicon tips. Previous work has been limited by stress in the cantilevers, thickness and size of the cantilevers, un-optimized electrical trace design, and/or a lack of a probing tip. Tests indicate amplitude resolution with self-sensing to be as good or better than optical detection, and sensitivities up to twice as good, with the same type cantilever. A tapping Mode Image of an evaporated gold film and force curves that compare optical and self-sensing detection methods are presented.
Otto A Smiseth - One of the best experts on this subject based on the ideXlab platform.
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noninvasive myocardial strain measurement by speckle tracking echocardiography validation against sonomicrometry and tagged magnetic resonance imaging
Journal of the American College of Cardiology, 2006Co-Authors: Brage H Amundsen, Thomas Hellevalle, Thor Edvardsen, Hans Torp, Jonas Crosby, Erik Lyseggen, Asbjorn Stoylen, Halfdan Ihlen, Joao A C Lima, Otto A SmisethAbstract:OBJECTIVES The aim of this study was to validate speckle tracking echocardiography (STE) as a method for angle-independent measurement of regional myocardial strain, using sonomicrometry and magnetic resonance imaging (MRI) tagging as reference methods. BACKGROUND Tissue Doppler imaging allows non-invasive measurement of myocardial strain in the left ventricle (LV), but is limited by angle dependency. METHODS Strain measurements with STE were obtained by a custom-made program that allowed tracking of two-dimensional motion of speckle patterns in a B-Mode Image. In anesthetized dogs, we compared LV long- and short-axis measurements by STE to sonomicrometry during preload changes and regional myocardial ischemia. Measurements in the two orthogonal axes were obtained simultaneously in a single imaging plane. In human subjects, long-axis strain by STE and MRI tagging were compared in multiple segments of the LV. RESULTS In the experimental study there was good correlation and agreement between STE and sonomicrometry for systolic strain in the long axis (r = 0.90, p < 0.001; 95% limits of agreement -4.4% to 5.0%) and systolic shortening in the short axis (r = 0.79, p < 0.001; -5.6% to 5.1%). In the clinical study, 80% of the segments could be analyzed, and correlation and agreement between STE and MRI tagging were good (r = 0.87, p < 0.001; -9.1% to 8.0%). CONCLUSIONS Speckle tracking echocardiography provides accurate and angle-independent measurements of LV dimensions and strains and has potential to become a clinical bedside tool for quantifying myocardial strain.
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noninvasive myocardial strain measurement by speckle tracking echocardiography validation against sonomicrometry and tagged magnetic resonance imaging
Journal of the American College of Cardiology, 2006Co-Authors: Brage H Amundsen, Thomas Hellevalle, Thor Edvardsen, Hans Torp, Jonas Crosby, Erik Lyseggen, Asbjorn Stoylen, Halfdan Ihlen, Joao A C Lima, Otto A SmisethAbstract:Objectives The aim of this study was to validate speckle tracking echocardiography (STE) as a method for angle-independent measurement of regional myocardial strain, using sonomicrometry and magnetic resonance imaging (MRI) tagging as reference methods. Background Tissue Doppler imaging allows non-invasive measurement of myocardial strain in the left ventricle (LV), but is limited by angle dependency. Methods Strain measurements with STE were obtained by a custom-made program that allowed tracking of two-dimensional motion of speckle patterns in a B-Mode Image. In anesthetized dogs, we compared LV long- and short-axis measurements by STE to sonomicrometry during preload changes and regional myocardial ischemia. Measurements in the two orthogonal axes were obtained simultaneously in a single imaging plane. In human subjects, long-axis strain by STE and MRI tagging were compared in multiple segments of the LV. Results In the experimental study there was good correlation and agreement between STE and sonomicrometry for systolic strain in the long axis (r = 0.90, p Conclusions Speckle tracking echocardiography provides accurate and angle-independent measurements of LV dimensions and strains and has potential to become a clinical bedside tool for quantifying myocardial strain.