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Computational Approach to Estimate Functional Significance of Stenotic Lesion of Coronary Artery
Duc Minh Tran(쩐득민),Minh Tuan Nguyen(웬민투안),Hyoung Gwon Choi(최형권),Hyuk-Jae Chang(장혁재),Sang-Wook Lee(이상욱) 대한기계학회 2017 대한기계학회 춘추학술대회 Vol.2017 No.11
Computed tomographic (CT) angiography often overestimates the significance of stenotic lesion of coronary and it leads to a need for functional diagnostic measurements. Currently, invasive pressure-wire-based fractional flow reserve (FFR) is becoming the standard of reference for assessing the physiological significance of coronary stenoses in clinical decisions regarding revascularization and exhibits favorable outcomes in identifying the ischemia-causing stenosis. A noninvasive approach for FFR prediction based on computational fluid dynamics with CT angiography was developed. Since the hemodynamic conditions in distal vascular beds highly affects the coronary flow structures, it is necessary to incorporate zero-dimensional (0D) lumped parameter network (LPN) model for coronary microvascular flow by coupling with 3D CFD simulation. This demonstrated high diagnostic and prognostic accuracy with a reduction of adverse events. MPI parallel algorithm based on domain decomposition method was applied for the 3D-0D coupled model of coronary flow dynamics simulations in a monolithic approach. In this paper, we introduce the development of clinically practical computational tool to estimate physiological significance of stenotic lesion of coronary with aims of accelerating clinical outcomes, basically by bench to bedside approach.
관상동맥 협착병변 형상인자와 혈류역학 기반 진단인자의 상관관계 수치해석 연구
쩐득민(Duc Minh Tran),웬비엣카이(Viet Khai Nguyen),웬민투안(Minh Tuan Nguyen),이상욱(Sang-Wook Lee) 대한기계학회 2018 大韓機械學會論文集B Vol.42 No.7
관상동맥 협착병변 심각도에 대한 기존의 혈관 협착률 기반 진단인자의 제한된 정확도로 인하여 최근 생리기능성 진단인자의 중요성이 높아지고 있다. 가장 대표적인 혈류역학 기반 생리기능성 진단인자인 심근분획혈류예비력(FFR)과 벽전단응력(WSS)가 일반적으로 협착병변의 여러 형상 특성인자에 의해 크게 영향을 받는 것으로 잘 알려져 있다. 본 연구에서는 협착병변의 다양한 형상특성인자를 고려한 혈관 모델을 설계하고 다중스케일 CFD 시뮬레이션을 수행한 후, FFR 및 WSS값과 협착병변 형상특성인자의 상관관계를 분석하였다. 기본적으로 혈관 협착률이 FFR과 WSS값에 가장 큰 영향을 미치는 것으로 나타났으며, 협착률이 높을수록, 협착부 형상(shape)의 영향이 커짐을 확인할 수 있었다. Due to the limited diagnostic accuracy of conventional evaluation by stenosis degree for coronary stenotic lesion severity, physiology-based functional indices have recently received much attention. Fractional flow reserve (FFR) and wall shear stress (WSS) are the most representative indices. These hemodynamics-based indices are closely related to blood flow characteristics downstream of stenosis which is greatly affected by the geometric features of stenosis. In this study, we considered major geometric features of stenotic lesions and investigated the correlation between the functional indices and the lesion-specific geometrical parameters by carrying out multi-scale CFD simulations. Lumen diameter reduction rate has the largest effect on the physiological indices and the effect of lesion shape becomes greater as the stenosis degree rises.
Nguyen Ho Minh Duy,Tran Anh Tuan,Nguyen Hai Duong,Tran Anh Tuan,Nguyen Kim Dao,Atsuo Yoshitaka,Jin Young Kim,Seung Ho Choi,Pham The Bao 한국정보기술학회 2016 한국정보기술학회논문지 Vol.14 No.5
MRI and CT images are the most popular formats assisting a doctor in diagnosis and treatment, but highly accurate segmentation is a challenging problem due to intensity inhomogeneity and environmental noises. In this paper, we introduce an appropriate and effective automatic approach to facilitate this problem in two stages. In the first stage, skull region is removed from the brain by morphological active contour and level set process. Moreover, in level set process, some AI rules are defined on slice positions of brain to increase the accuracy. In the second stage, a modified EM method is performed on the resultant skull-stripping image to identify some candidate main regions of CSF (cerebro-spinal fluid), GM (gray matter), and WM (white matter). The candidate regions are then re-estimated into the proper CSF, GM, and WM through a Bayesian Estimation Process. The experimental results show that the proposed approach obtains a robust segmentation for IBSR, OASIS and Korean Hospital database. With the proposed AI-rules, the level set method gets good skull-stripping images regardless of MRI slice position in bran. Also, Bayesian postprocessing can improve the segmentation performance by 10~15% in CSF, GM and WM ratios compared the basic EM algorithm.
관상동맥 협착부 형상 특성 인자와 혈류역학적 생리기능성 진단인자의 상관관계에 대한 수치 해석
쩐득민(Duc Minh Tran),웬민투안(Minh Tuan Nguyen),이상욱(Sang-Wook Lee) 대한기계학회 2017 대한기계학회 춘추학술대회 Vol.2017 No.11
The functional significance rather than conventional evaluation by geometric lumen area reduction of coronary stenosis has recently received much attention. Hemodynamics based diagnostic parameters such as fractional flow reserve (FFR) and wall shear stress (WSS) are most representative physiological indices for identifying lesion severity. Previous studies demonstrated superior performance of FFR and WSS to identify ischemia-causing coronary stenosis. These hemodynamic parameters are closely related to blood flow characteristics downstream of stenosis which is greatly affected by geometric shape of stenosis. Although the in vivo geometry of stenosis is irregular and complex, we extracted major feature geometric parameters and investigate the effect on the FFR and WSS. In this study, we carried out 3D computational fluid dynamics simulations for coronary artery models with considering various stenosis geometric parameters and performed correlation analysis.
( Minh Hai Pham ),( Quan Anh Tuan Le ),( Hoang Bac Nguyen ),( Quang Hung Vu ),( Thai Ngoc Huy Tran ),( Hang Dang Khoa N Guyen ),( Thi Ngoc Sang Duong ),( Van Toan Tran ) 대한간학회 2020 춘·추계 학술대회 (KASL) Vol.2020 No.1
Aims: Laparoscopic pancreaticoduodenectomy (LPD) is considered as a safe and effective procedure in well - selected patients and appropriate surgical technique. Our aim is to evaluate suitability of using protocol for LPD in treatment of periampullary cancer at a single team. Methods: case series Results: Indication for LPD included 37 cases with resectable tumors which were classified basing on NCCN. All witness evaluation risk of complications with PREPARE score, ASA and evaluation risk of postoperative pancreatic fistula (POPF) with FRS classification. There were 2 open conversions because of vein resections, accounting for 5.4%. Standard lymphadenectomy was performed in all of 37 cases. In term of PREPARE score, major complications (Clavien - Dindo >= III) were 17.8%, 0% and 0% (5/28, 0/5 and 0/2 cases) in low risk, intermediate risk and high risk group, respectively. All of cases had ASA I or II. POPF happened 11.1% (1/9), 4.1% (1/24) and 50% (1/2) in low risk, intermediate risk and high risk group, respectively. Frozen section was needed for R0 margin. Retrieved lymph nodes was 8 - 18 with 12 lymph nodes in average. Conclusions: Indication for LPD with resectable tumors is acceptable. ASA I or II is a safe measure to select patient for LPD. FRS classification shows appropriation to evaluate risk of POPF.
Tran, Khanh Long,Phung, Xuan Son,Kim, Bao Giang,Phan, Thi Hai,Doan, Thi Thu Huyen,Luong, Ngoc Khue,Pham, Thi Quynh Nga,Nguyen, Tuan Lam,Hoang, Van Minh,Le, Thi Thanh Huong Asian Pacific Journal of Cancer Prevention 2016 Asian Pacific journal of cancer prevention Vol.17 No.no.sup1
Evidence shows that tobacco advertising and promotion activities may increase tobacco consumption and usage, especially in youth. Despite the regulation on prohibiting advertisement of any tobacco product, tobacco advertisement and promotion activities are still common in Vietnam. This article presents current exposure to tobacco advertising and promotion (TAP) among school children aged 13 to 15 years in Vietnam in 2014 and potential influencing factors. Data from the Global Youth Tobacco Survey 2014 in Vietnam covering 3,430 school aged children were used. Both descriptive and analytical statistics were carried out with Stata 13 statistical software. Binary logistic regression was applied to explain the exposure to TAP among youth and examine relationships with individual factors. A significance level of p<0.05 and sampling weights were used in all of the computations. In the past 30 days, 48.6% of the students experienced exposure to at least 1 type of tobacco advertising or promotion. Wearing or otherwise using products related to tobacco was the most exposure TAP type reported by students (22.3%). The internet (22.1), points of sales (19.2) and social events (11.5) were three places that students aged 13-15 frequently were exposed to TAP. Binary logistic results showed that gender (female vs male) (OR = 0.61, 95%CI: 0.52 - 0.71), susceptibility to smoking (OR = 2.12, 95%CI: 1.53 - 2.92), closest friends' smoked (OR = 1.43, 95%CI: 1.2 - 1.7) and parents smoking status (OR = 2.83, 95%CI: 1.6 - 5.01) were significantly associated with TAP exposure among school-aged children. The research findings should contribute to effective implementation of measures for preventing and controlling tobacco use among students aged 13-15 in Viet Nam.
Minh Canh Vu,Tuan Sang Tran,배영한,유민지,Vu Chi Doan,이재흥,안태규,김성룡 한국고분자학회 2018 Macromolecular Research Vol.25 No.6
The self-assembled oxidized carbon nanotubes (oCNTs) with the silane functionalized hexagonal boron nitrides (oCNTs@fBN) via electrostatic interaction were used to improve the thermal conductivity while maintaining the electrical insulation properties of the epoxy composites. The oCNTs were separately immobilized on the edges of hexagonal boron nitride (hBN), which prevent oCNTs from continuously contacting with each other. The thermal conductivity and volume resistivity of oCNTs@fBN filler loaded epoxy composites were measured and compared with the epoxy composites with a filler of hBN, a mixed filler of oCNTs, and silane functionalized hBN (fBN). The thermal conductivity of the epoxy composites containing 20wt% of oCNTs@fBN10 was 1.26 W·m-1·K-1, which is higher than 600% compared to that of neat epoxy and the volume resistivity of the epoxy composites was in an insulation region even at high content of oCNTs@fBN filler. The significant improvement in thermal conductivity was attributed to the formation of linkages between oCNTs and fBN and the good compatibility of oCNTs@fBN in the epoxy matrix.
Minh Canh Vu,Tuan Sang Tran,배영한,유민지,Vu Chi Doan,이재흥,안태규,김성룡 한국고분자학회 2018 Macromolecular Research Vol.26 No.6
The self-assembled oxidized carbon nanotubes (oCNTs) with the silane functionalized hexagonal boron nitrides (oCNTs@fBN) via electrostatic interaction were used to improve the thermal conductivity while maintaining the electrical insulation properties of the epoxy composites. The oCNTs were separately immobilized on the edges of hexagonal boron nitride (hBN), which prevent oCNTs from continuously contacting with each other. The thermal conductivity and volume resistivity of oCNTs@fBN filler loaded epoxy composites were measured and compared with the epoxy composites with a filler of hBN, a mixed filler of oCNTs, and silane functionalized hBN (fBN). The thermal conductivity of the epoxy composites containing 20wt% of oCNTs@fBN10 was 1.26 W·m-1·K-1, which is higher than 600% compared to that of neat epoxy and the volume resistivity of the epoxy composites was in an insulation region even at high content of oCNTs@fBN filler. The significant improvement in thermal conductivity was attributed to the formation of linkages between oCNTs and fBN and the good compatibility of oCNTs@fBN in the epoxy matrix.