Browsing by Author "Hsieh, Yao-Sheng"

Now showing 1 - 11 of 11

Brain structure and spatial sensitivity profile assessing by near-infrared spectroscopy modeling based on 3D MRI data
(2013-03-01)
Chuang, Ching-Cheng
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Chen, Chung-Ming
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Hsieh, Yao-Sheng
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Liu, Tsan-Chi
;
Sun, Chia-Wei
The goal of this study is to prove that the light propagation in the head by used the 3-D optical model from in vivo MRI data set can also provide significant characteristics on the spatial sensitivity of cerebral cortex folding geometry based on Monte Carlo simulation. Thus, we proposed a MRI based approach for 3-D brain modeling of near-infrared spectroscopy (NIRS). In the results, the spatial sensitivity profile of the cerebral cortex folding geometry and the arrangement of source-detector separation have being necessarily considered for applications of functional NIRS. The optimal choice of source-detector separation is suggested within 33.5 cm by the received intensity with different source-detector separations and the ratio of received light from the gray and white matter layer is greater than 50%. Additionally, this study has demonstrated the capability of NIRS in not only assessing the functional but also detecting the structural change of the brain by taking advantage of the low scattering and absorption coefficients observed in CSF of sagittal view. ((c) 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)
Characterization of tooth structure and the dentin-enamel zone based on the Stokes-Mueller calculation
(2012-11-01)
Sun, Chia-Wei
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Hsieh, Yao-Sheng
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Ho, Yi-Ching
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Jiang, Cho-Pei
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Chuang, Ching-Cheng
This is the first study of dentin-enamel zone (DEZ) identification with tooth structure characterization based on the optical Stokes-Mueller measurement. Stokes vectors of a cross-sectional tooth slice were measured using various polarization inputs. The direction of the DEZ is different in enamel and dentin structures; therefore, the Stokes profiles can specifically characterize the structures based on the DEZ. This optical method, using polarimetry, provides a useful tool for characterizing tooth. (c) 2012 Society of Photo-Optical Instrumentation Engineers (SPIE). [DOI: 10.1117/1.JBO.17.11.116026]
Dental Calculus Image Based on Optical Coherence Tomography
(2011)
Hsieh, Yao-Sheng
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Ho, Yi-Ching
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Lee, Shyh-Yuan
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Chuang, Ching-Cheng
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Wang, Chun-Yang
In this study, the dental calculus was characterized and imaged by means of swept-source optical coherence tomography (SSOCT). The refractive indices of enamel, dentin, cementum and calculus were measured as 1.625+/-0.024, 1.534+/-0.029, 1.570+/-0.021 and 1.896+/-0.085, respectively. The dental calculus lead strong scattering property and thus the region can be identified under enamel with SSOCT imaging. An extracted human tooth with calculus was covered by gingiva tissue as in vitro sample for SSOCT imaging.
Dental Optical Coherence Tomography
(2013-07-01)
Hsieh, Yao-Sheng
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Ho, Yi-Ching
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Lee, Shyh-Yuan
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Chuang, Ching-Cheng
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Tsai, Jui-che
This review paper describes the applications of dental optical coherence tomography (OCT) in oral tissue images, caries, periodontal disease and oral cancer. The background of OCT, including basic theory, system setup, light sources, spatial resolution and system limitations, is provided. The comparisons between OCT and other clinical oral diagnostic methods are also discussed.
Diffuse Optical Multipatch Technique for Tissue Oxygenation Monitoring: Clinical Study in Intensive Care Unit
(2012-01-01)
Wang, Chun-Yang
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Chuang, Ming-Lung
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Liang, Shinn-Jye
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Tsai, Jui-che
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Chuang, Ching-Cheng
Diffuse optical multipatch technique is used to assess spatial variations in absorption and scattering in biological tissue, by monitoring changes in the concentration of oxyhemoglobin and deoxyhemoglobin. In our preliminary study, the temporal tracings of tissue oxygenation are measured using diffuse optical multipatch measurement and a venous occlusion test, employing normal subjects and ICU patients suffering from sepsis and heart failure. In experiments, obvious differences in tissue oxygenation signals were observed among all three groups. This paper discusses the physiological relevance of tissue oxygenation with respect to disease.
Diffuser-Aided Diffuse Optical Imaging for Breast Tumor: A Feasibility Study Based on Time-Resolved Three-Dimensional Monte Carlo Modeling
(2012-05-01)
Chuang, Ching-Cheng
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Lee, Chia-Yen
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Chen, Chung-Ming
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Hsieh, Yao-Sheng
;
Liu, Tsan-Chi
This study proposed diffuser-aided diffuse optical imaging (DADOI) as a new approach to improve the performance of the conventional diffuse optical tomography (DOT) approach for breast imaging. The 3-D breast model for Monte Carlo simulation is remodeled from clinical MRI image. The modified Beer-Lambert's law is adopted with the DADOI approach to substitute the complex algorithms of inverse problem for mapping of spatial distribution, and the depth information is obtained based on the time-of-flight estimation. The simulation results demonstrate that the time-resolved Monte Carlo method can be capable of performing source-detector separations analysis. The dynamics of photon migration with various source-detector separations are analyzed for the characterization of breast tissue and estimation of optode arrangement. The source-detector separations should be less than 4 cm for breast imaging in DOT system. Meanwhile, the feasibility of DADOI was manifested in this study. In the results, DADOI approach can provide better imaging contrast and faster imaging than conventional DOT measurement. The DADOI approach possesses great potential to detect the breast tumor in early stage and chemotherapy monitoring that implies a good feasibility for clinical application.
Hemodynamic analysis of patients in intensive care unit based on diffuse optical spectroscopic imaging system
(2010)
Hsieh, Yao-Sheng
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Wang, Chun-Yang
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Ling, Yo-Wei
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Chuang, Ming-Lung
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Chuang, Ching-Cheng
Diffuse optical spectroscopic imaging (DOSI) is a technique to assess the spatial variation in absorption and scattering properties of the biological tissues and provides the monitoring of changes in concentrations of oxy-hemoglobin and deoxy-hemoglobin. In our preliminary study, the temporal tracings of hemodynamic oxygenation are measured with DOSI and venous occlusion test (VOT) from normal subjects, patients with heart failure and patients with sepsis in intensive care unit (ICU). In experiments, the obvious differences of hemodynamic signals can be observed among the three groups. The physiological relevance of VOT hemodynamics with respect to diseases is also discussed in this paper.
Near-Infrared Brain Volumetric Imaging Method: A Monte Carlo Study
(2012-05-01)
Chuang, Ching-Cheng
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Wang, Pei-Ning
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Chen, Wei-Ta
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Lan, Tsuo-Hung
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Chen, Chung-Ming
"The symptom of brain volumetric changes may provide significant biomarker to predict progressive dementia. The brain volumetric changes of prefrontal cortex are highly associated with many neurodegenerative diseases. Besides, brain atrophy reveals the expanded interhemispheric fissure and the concomitant increasing cerebrospinal fluid volume. Thus, the quantitative assessment of brain volumetric changes is an important consideration for clinical studies of neurodegenerative diseases. In this study, we first proposed an approach that uses near-infrared brain volumetric imaging to detect brain volumetric changes. The healthy, aged, and typical Alzheimer's disease (AD) brains were modeled with different characterization of brain volumetric changes from in vivo MRI data based on time-resolved 3-D Monte Carlo simulation. In the results, the significant difference of prefrontal cortex structure can be observed among healthy, aged, and AD brain with various source-detector separations in sagittal view. Our study shows that the near-infrared brain volumetric imaging can be an indicator of brain atrophy for clinical application of neurodegenerative diseases with patient-oriented measurement."
Patient-oriented simulation based on Monte Carlo algorithm by using MRI data
(2012-04-17)
Chuang, Ching-Cheng
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Lee, Yu-Tzu
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Chen, Chung-Ming
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Hsieh, Yao-Sheng
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Liu, Tsan-Chi
Background: Although Monte Carlo simulations of light propagation in full segmented three-dimensional MRI based anatomical models of the human head have been reported in many articles. To our knowledge, there is no patient-oriented simulation for individualized calibration with NIRS measurement. Thus, we offer an approach for brain modeling based on image segmentation process with in vivo MRI T1 three-dimensional image to investigate the individualized calibration for NIRS measurement with Monte Carlo simulation. Methods: In this study, an individualized brain is modeled based on in vivo MRI 3D image as five layers structure. The behavior of photon migration was studied for this individualized brain detections based on three-dimensional time-resolved Monte Carlo algorithm. During the Monte Carlo iteration, all photon paths were traced with various source-detector separations for characterization of brain structure to provide helpful information for individualized design of NIRS system. Results: Our results indicate that the patient-oriented simulation can provide significant characteristics on the optimal choice of source-detector separation within 3.3 cm of individualized design in this case. Significant distortions were observed around the cerebral cortex folding. The spatial sensitivity profile penetrated deeper to the brain in the case of expanded CSF. This finding suggests that the optical method may provide not only functional signal from brain activation but also structural information of brain atrophy with the expanded CSF layer. The proposed modeling method also provides multi-wavelength for NIRS simulation to approach the practical NIRS measurement. Conclusions: In this study, the three-dimensional time-resolved brain modeling method approaches the realistic human brain that provides useful information for NIRS systematic design and calibration for individualized case with prior MRI data.
Subgingival calculus imaging based on swept-source optical coherence tomography
(2011-07-01)
Hsieh, Yao-Sheng
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Ho, Yi-Ching
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Lee, Shyh-Yuan
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Lu, Chih-Wei
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Jiang, Cho-Pei
We characterized and imaged dental calculus using swept-source optical coherence tomography (SS-OCT). The refractive indices of enamel, dentin, cementum, and calculus were measured as 1.625 +/- 0.024, 1.534 +/- 0.029, 1.570 +/- 0.021, and 2.097 +/- 0.094, respectively. Dental calculus leads strong scattering properties, and thus, the region can be identified from enamel with SS-OCT imaging. An extracted human tooth with calculus is covered with gingiva tissue as an in vitro sample for tomographic imaging. (C) 2011 Society of Photo-Optical Instrumentation Engineers (SPIE). [DOI: 10.1117/1.3602851]
The utility of far-infrared illumination in oxygenation dynamics as measured with near-infrared spectroscopy
(2012-10-01)
Wang, Chun-Yang
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Chuang, Ming-Lung
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Chuang, Ching-Cheng
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Hsieh, Yao-Sheng
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Sun, Chia-Wei
Near-infrared spectroscopy (NIRS) is a noninvasive method for measuring the oxygenation in muscle and other tissues in vivo. For quantitative NIRS measurement of oxygenation dynamics, the vessel-occlusion test was usually applied as physiological intervention. There are several drawbacks of the vessel-occlusion method that include skin contact, uncomfortable and microcirculation block of patients. Thus, we propose the far-infrared (FIR) illumination as a new physiological intervention method in this paper. Our preliminary result shows a linear correlation of oxygenation dynamic signals between FIR illumination and arterial-occlusion test (AOT) that implies the FIR illumination could be applied for hemodynamic response measurement in clinical diagnosis. ((c) 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)