62 results on '"Chaichana T"'
Search Results
2. Micro-siting Wind Resource Assessment and Near Shore Wind Farm Analysis in Pakpanang District, Nakhon Si Thammarat Province, Thailand
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Waewsak, J., Chaichana, T., Chancham, C., Landry, M., and Gagnonc, Y.
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- 2014
- Full Text
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3. Effect of blade number and angle on the characteristics of the savonius type wind turbine
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Chaichana, T, primary and Thongdee, S, additional
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- 2019
- Full Text
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4. Patient-specific 3D printed models of renal tumours using home-made 3D printer in comparison with commerical 3D printer
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Liu, D., Sun, Zhonghua, Chaichana, T., Ducke, W., Fan, Z., Liu, D., Sun, Zhonghua, Chaichana, T., Ducke, W., and Fan, Z.
- Abstract
The purpose of this study is to create three-dimensional (3D) printed models of renal tumours with use of home-made and commercially available 3D printers and compare the accuracy of 3D printed models in delineating renal tumours and costs associated with 3D printing between these 3D printers. Life-size 3D printed kidney models of two patients with suspected renal cell carcinoma were generated with use of high-resolution contrast-enhanced computed tomography (CT) images which were post-processed and segmented to show normal renal anatomy and renal tumours. Measurements of tumour diameters were performed at left to right and craniocaudal dimensions and were compared on 2D axial, multiplanar reformation (MPR) and 3D volume rendering CT images with those on 3D physical models to determine the accuracy differences between these techniques. 3D printed models were successfully generated by both commercial and home-made 3D printers with accurately replicating renal anatomy and renal tumours. Although there was no significant difference in measuring tumour diameters, measurements on 3D printed models between commercial and home-made 3D printers were within 0.9 mm in these two cases. Similarly, a good correlation was found in measurements made between 3D volume rendering images and 3D printed models with differences between 0.85 and 0.98 mm, 0.69 and 0.73 mm, for cases 1 and 2, respectively. Measurements in 3D printed models exceeded 2D axial and MPR measurements by an average of more than 1.5 mm. The printing cost per kidney model was US$1 and US$200 for home-made and commercial 3D printers, respectively. This study shows the feasibility of creating 3D printed models of demonstrating renal anatomy and renal tumours with use of home-made 3D printer with accuracy similar to that from commercial 3D printer, but at a much lower cost.
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- 2018
5. Automatic Location of Blood Vessel Bifurcations in Digital Eye Fundus Images
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Chaichana, T., Sun, Zhonghua, Barrett-Baxendale, M., Nagar, A., Chaichana, T., Sun, Zhonghua, Barrett-Baxendale, M., and Nagar, A.
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Retinal blood vessels are linked with hypertension and cardiovascular disease. It is generally known that vascular bifurcation is mainly involved in varying blood flow velocity as well as its pressure. This paper presents an efficient method for automatic location of blood vessel bifurcations in digital eye fundus images. The proposed algorithm comprised of three main steps: image enhancement, fuzzy clustering, and searching vascular bifurcation. The purposed algorithm revealed successful detection of bifurcations upon test images. Results showed improved diagnostic accuracy in identifying bifurcations with use of the proposed algorithm and encourage its use for further applications such as image registration, personal identification and pre-clinical scanning of retina diagnosis.
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- 2017
6. An investigation of correlation between left coronary bifurcation angle and hemodynamic changes in coronary stenosis by coronarycomputed tomography angiography-derived computational fluid dynamics
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Sun, Zhonghua, Chaichana, T., Sun, Zhonghua, and Chaichana, T.
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Background: To investigate the correlation between left coronary bifurcation angle and coronary stenosis as assessed by coronary computed tomography angiography (CCTA)-generated computational fluid dynamics (CFD) analysis when compared to the CCTA analysis of coronary lumen stenosis and plaque lesion length with invasive coronary angiography (ICA) as the reference method. Methods: Thirty patients (22 males, mean age: 59±6.9 years) with calcified plaques at the left coronary artery were included in the study with all patients undergoing CCTA and ICA examinations. CFD simulation was performed to analyze hemodynamic changes to the left coronary artery models in terms of wall shear stress, wall pressure and flow velocity, with findings correlated to the coronary stenosis and degree of bifurcation angle. Calcified plaque length was measured in the left coronary artery with diagnostic value compared to that from coronary lumen and bifurcation angle assessments. Results: Of 26 significant stenosis at left anterior descending (LAD) and 13 at left circumflex (LCx) on CCTA, only 14 and 5 of them were confirmed to be >50% stenosis at LAD and LCx respectively on ICA, resulting in sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of 100%, 52%, 49% and 100%. The mean plaque length was measured 5.3±3.6 and 4.4±1.9 mm at LAD and LCx, respectively, with diagnostic sensitivity, specificity, PPV and NPV being 92.8%, 46.7%, 61.9% and 87.5% for extensively calcified plaques. The mean bifurcation angle was measured 83.9±13.6º and 83.8±13.3º on CCTA and ICA, respectively, with no significant difference (P=0.98). The corresponding sensitivity, specificity, PPV and NPV were 100%, 78.6%, 84.2% and 100% based on bifurcation angle measurement on CCTA, 100%, 73.3%, 78.9% and 100% based on bifurcation angle measurements on ICA, respectively. Wall shear stress was noted to increase in the LAD and LCx models with significant stenosis and wider angulat
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- 2017
7. Computational fluid dynamic analysis of calcified coronary plaques: Correlation between hemodynamic changes and cardiac image analysis based on left coronary bifurcation angle and lumen assessments
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Sun, Zhonghua, Chaichana, T., Sun, Zhonghua, and Chaichana, T.
- Abstract
The purpose of this study was to determine the relationship between left coronary bifurcation angle and significant coronary stenosis with use of coronary CT angiography (CCTA)-generated computational fluid dynamics (CFD) analysis when compared to the CCTA analysis of coronary lumen stenosis with invasive coronary angiography (ICA) as the reference method. Eleven patients with calcified plaques at the left coronary artery tree who underwent CCTA and ICA examinations were included in the study. CFD simulation of left coronary models was performed to analyse hemodynamic changes including wall shear stress, wall pressure and flow velocity. The mean bifurcation angle was measured 83.3 ± 17.1° and 83.3 ± 17.0° on CCTA and ICA, respectively, with no significant difference (p=0.99). Of 15 significant stenosis at left anterior descending (LAD) and left circumflex (LCx) on CCTA, only 3 of them were confirmed to be > 50% stenosis on ICA. Wall shear stress was noted to increase in the LAD and LCx models with significant stenosis and wider angulation (> 80°), but remained no change in most of the other coronary models with no significant stenosis and narrower angulation. Wall pressured was decreased at the significant stenotic lesions, while flow velocity was increased with flow turbulence at the post-stenotic sites. This study further clarifies the direct correlation between left coronary bifurcation angle and significant stenosis, with angulation measurement being more accurate than lumen assessment for diagnosing significant stenosis.
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- 2016
8. A systematic review of computational fluid dynamics in type B aortic dissection
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Sun, Zhonghua, Chaichana, T., Sun, Zhonghua, and Chaichana, T.
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- 2016
9. Electric prosthetic hand activated using two-channel surface electromyography
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Supakitamonphan, C., primary, Suksri, S., additional, Pramunrueang, N., additional, and Chaichana, T., additional
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- 2015
- Full Text
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10. Computational fluid dynamics analysis of the effect of plaques in the left coronary artery
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Chaichana, T, Sun, Zhonghua, Jewkes, James, Chaichana, T, Sun, Zhonghua, and Jewkes, James
- Abstract
This study was to investigate the hemodynamic effect of simulated plaques in left coronary artery models, which were generated from a sample patient’s data. Plaques were simulated and placed at the left main stem and the left anterior descending (LAD) to produce at least 60% coronary stenosis. Computational fluid dynamics analysis was performed to simulate realistic physiologicalconditions that reflect the in vivo cardiac hemodynamics, and comparison of wall shear stress (WSS) between Newtonian and non-Newtonian fluid models was performed. The pressure gradient (PSG) and flow velocities in the left coronary artery were measured and compared in the left coronary models with and without presence of plaques during cardiac cycle. Our results showed that the highest PSG was observed in stenotic regions caused by the plaques. Low flow velocity areas were found at postplaque locations in the left circumflex, LAD, and bifurcation. WSS at the stenotic locations was similar between the non-Newtonian and Newtonian models although some more details were observed with non-Newtonian model. There is a direct correlation between coronary plaques and subsequent hemodynamic changes, based on the simulation of plaques in the realistic coronary models.
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- 2012
11. Computational fluid dynamics analysis of the effect of simulated plaques in the left coronary artery: A preliminary study.
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F. Chan, D. Marinova, R.S. Anderssen, Chaichana, T., Jewkes, James, Sun, Zhonghua, F. Chan, D. Marinova, R.S. Anderssen, Chaichana, T., Jewkes, James, and Sun, Zhonghua
- Abstract
Background: Atherosclerosis is the most common cause of coronary artery disease which is formed by plaque presence inside the artery wall leading to blockage of the blood supply to the heart muscle. The mechanism of atherosclerotic development is dependent on the blood flow variations in the artery wall during cardiac cycles. Characterization of plaque components and investigation of the plaques with subsequent coronary artery stenosis and myocardial dysfunction has been extensively studied in the literature. However, little is known about the effect of plaques on hemodynamic changes to the coronary artery, to the best of our knowledge. Investigation of the position of plaques in the coronary artery and its corresponding regional hemodynamic effects will provide valuable information for prediction of the coronary artery disease progression. The aim of this study is to investigate the effect of simulated plaques in the left coronary artery using computational fluid dynamics. Methods: A left coronary artery model was generated based on a computed tomography data in a patient suspected of coronary artery disease. The model consists of the left main coronary artery, left anterior descending and left circumflex, together with side branches. Simulated coronary plaques were created and placed in the left main coronary artery and left anterior descending with a resultant lumen stenosis of more than 50%. The blood rheology and pulsatile velocity at the left coronary artery were applied to simulate the realistic physiological situation. A transient simulation was performed to demonstrate the hemodynamic changes during cardiac phases. The flow velocity pattern, wall shear stress and wall pressure were measured at peak systolic and middle diastolic phases in the models with and without presence of plaques.Results: Our results showed that the flow change due to the simulated coronary plaques demonstrated a large circulation region at the left coronary bifurcation, and the veloci
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- 2011
12. Fenestrated stent graft repair of abdominal aortic aneurysm: Hemodynamic analysis of effect of fenestrated stents on renal arteries
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Sun, Zhonghua, Chaichana, T., Sun, Zhonghua, and Chaichana, T.
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Purpose: To investigate the hemodynamic effect of fenestrated stents on renal arteries using a fluid structure interaction method. Materials and Methods: Two representative patients with abdominal aortic aneurysm treated with fenestrated stent grafts were selected in the study. 3D realistic aorta models for the main artery branches and aneurysm were generated based on multislice computed tomographic scans from 2 patients with different aortic geometries. The simulated fenestrated stents were designed and modelled based on 3D intraluminal appearance, and placed inside the renal artery to reflect the actual patients treatment with an intra-aortic protrusion of 5.0-7.0 mm. The stent wire thickness was simulated with a diameter of 0.4 mm and hemodynamic analysis was performed at different cardiac cycles. Results: Our results showed that the effect of fenestrated stent wires on renal blood flow was minimal as the flow velocity was not significantly affected when compared to that calculated at pre-stent graft implantation, despite presence of recirculation patterns at the proximal part of the renal arteries. Wall pressure was found to decrease significantly after fenestration, however, no significant change of wall shear stress was noticed post-fenestration, although it was shown to decrease slightly at the proximal aneurysm necks. Conclusion: Our analysis demonstrates that hemodynamic effect of fenestrated renal stents on renal arteries is insignificant. Further studies are needed to investigate the effect of different lengths of stent protrusion with variable stent thicknesses on renal blood flow, which is valuable for understanding the long-term outcomes of fenestrated repair.
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- 2010
13. Investigation of hemodynamic changes in abdominal aortic aneurysms treated with fenestrated endovascular grafts
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Sun, Zhonghua, Chaichana, T., Allen, Y., Sangworasil, M., Tungjitkusolmun, S., Hartley, D., Lawrence-Brown, Michael, Sun, Zhonghua, Chaichana, T., Allen, Y., Sangworasil, M., Tungjitkusolmun, S., Hartley, D., and Lawrence-Brown, Michael
- Abstract
Fenestrated stent grafts are becoming widely used in clinical practice to treat patients with complicated aortic aneurysms, with short to mid-term satisfactory outcomes being achieved. However, long-term results are yet to be determined. One of the main concerns about the safety of fenestrated repair is the patency of fenestrated renal arteries and subsequent renal function. The purpose of this study is to investigate the hemodynamic changes in patients treated with fenestrated stent grafts using a two-way fluid-structure interaction. 4 patients undergoing fenestrated stent graft repair were selected for inclusion in our analysis. All of the fenestrated renal arteries remained patent after implantation of stent grafts with one patient developing post-procedural complication, endoleak. Our results showed that with insertion of fenestrated stents into the renal arteries with variable lengths, no significant changes of blood flow velocity were noticed based on the flow analysis. Our preliminary study indicates the safety of fenestrated stent grafts, however, further studies are required to verify the long-term outcome of this procedure.
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- 2009
14. Hemodynamic Effect of Calcifed Plaque on Blood Flow in Carotid Artery Disease: A Preliminary Study
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The 3rd International Conference on Bioinformatics and Biomedical Engineering (iCBBE) 2009, Sun, Zhonghua, Ng, Curtise, Bibombe, P., Chaichana, T., The 3rd International Conference on Bioinformatics and Biomedical Engineering (iCBBE) 2009, Sun, Zhonghua, Ng, Curtise, Bibombe, P., and Chaichana, T.
- Abstract
The purpose of the study is to investigate the hemodynamic effect of calcified carotid plaque on blood flow in patients diagnosed with carotid artery disease. Two carotid artery models were generated based on a patient data, with normal and calcified carotid artery appearances. Circular calcified carotid plaque was found at the carotid bifurcation based on 3D computed tomography images. A computational fluid dynamics was performed to analyze the changes of blood flow in different situations. Our results showed that apparent turbulence was found in the diastolic phase at the carotid bifurcation in normal carotid artery geometry. In the presence of the calcified plaque, the flow velocity was increased to some extent, indicating the effect of plaque on hemodynamic changes. Wall shear stress was noticed to be maximal at the aortic bifurcation, and this indicates the potential risk of developing stenosis at this area. Our preliminary study demonstrates fluid structure interaction between calcified plaque and artery in terms of flow changes and wall shear stress.
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- 2009
15. Hemodynamic effect of calcifed plaque on blood flow in carotid artery disease: A preliminary study - Hemodynamic effect of calcified plaque
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Sun, Zhonghua, Mwipatayi, B., Chaichana, T., Ng, Curtise Kin Cheung, Sun, Zhonghua, Mwipatayi, B., Chaichana, T., and Ng, Curtise Kin Cheung
- Abstract
The purpose of the study is to investigate the hemodynamic effect of calcified carotid plaque on blood flow in patients diagnosed with carotid artery disease. Two carotid artery models were generated based on a sample patient data, with normal and calcified carotid artery appearances. Circular calcified carotid plaque was found at the carotid bifurcation based on 3D computed tomography images. A computational fluid dynamics was performed to analyze the changes of blood flow in different situations. Our results showed that apparent turbulence was found in the diastolic phase at the carotid bifurcation in normal carotid artery geometry. In the presence of the calcified plaque, the flow velocity was increased to some extent, indicating the effect of plaque on hemodynamic changes. Wall shear stress was noticed to decrease at the aortic branches, and this indicates the potential risk of developing stenosis at this area. Our preliminary study demonstrates fluid structure interaction between calcified plaque and artery in terms of flow changes and wall shear stress. ©2009 IEEE.
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- 2009
16. 3D virtual intravascular endoscopy visualization of coronary artery plaques: Virtual intravascular endoscopy of coronary plaques
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Sun, Zhonghua, Chaichana, T., Dimpudus, F., Adipranoto, J., Nugroho, J., Sun, Zhonghua, Chaichana, T., Dimpudus, F., Adipranoto, J., and Nugroho, J.
- Abstract
The purpose of the study is to investigate the potential diagnostic value of 3D virtual intravascular endoscopy in the visualization of coronary artery plaques in patients with suspected coronary artery disease. Ten patients suspected of coronary artery disease undergoing 64-slice computed tomography scans were included in the study. Four main coronary artery branches including right coronary artery, left main stem, left anterior descending and left circumflex were assessed using virtual intravascular endoscopy with emphasis on the intraluminal appearance of coronary plaques (calcified and noncalcified plaques). Position of the plaques and degree of vessel stenosis was compared with 2D axial images in each patient. Coronary artery disease with >50% stenosis was found in 6 patients involving 7 left anterior descending and 3 right coronary artery branches. Left anterior descending branch was commonly affected with extensive calcification, while more than half of the right coronary arteries were involved with noncalcified plaques. Our results showed that virtual intravascular endoscopy provides unique information of the coronary plaques by demonstrating the intraluminal configuration of coronary plaques, position of the plaques in relation to the artery branches. Both calcified and noncalcified plaques can be identified on virtual endoscopy images. Further studies are needed to clarify the role of virtual intravascular endoscopy in the quantification of plaque volume, stratification of patients suffering from coronary artery disease and patients management. ©2009 IEEE.
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- 2009
17. 3D virtual intravascular endoscopy visualization of coronary artery plaques
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IEEE, Sun, Zhonghua, Chaichana, T., Dimpudus, F., Adipranotob, J.D., Nugrohob, J., IEEE, Sun, Zhonghua, Chaichana, T., Dimpudus, F., Adipranotob, J.D., and Nugrohob, J.
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- 2009
18. Investigation of hemodynamic effect of stent wires on renal arteries in patients with abdominal aortic aneurysms treated with suprarenal stent grafts
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Sun, Zhonghua, Chaichana, T., Sun, Zhonghua, and Chaichana, T.
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The purpose of the study was to investigate the hemodynamic effect of stent struts (wires) on renal arteries in patients with abdominal aortic aneurysms (AAA) treated with suprarenal stent grafts. Two sample patients with AAA undergoing multislice CT angiography pre-and post-suprarenal fixation of stent grafts were selected for inclusion in the study. 3D aorta models (4 in total) containing the main aortic artery branches were generated from the multislice CT datasets. Four types of configurations of stent wires crossing the renal artery ostium, namely single wire central crossing, single wire peripherally crossing, V-shaped wire centrally crossing and multiple wires peripherally crossing were simulated in the segmented aorta models. The blood flow pattern and flow velocity to the renal arteries pre-and post-stent grafting were analyzed and compared using a two-way fluid structure interaction analysis. The stent wire thickness was simulated with a diameter of 0.4 mm, 1.0 mm and 2.0 mm, and hemodynamic analysis was performed at different cardiac cycles. Our results showed that the interference of stent wires with renal blood flow was determined by the number and configuration of stent wires crossing the renal artery ostium. The flow velocity was found to decrease significantly with multiple stent wires, especially the V-shaped type crossing the renal artery ostium, and with the wire thickness being 1.0 mm and 2.0 mm. No significant difference of flow velocity was noticed with a single wire crossing, regardless of variable simulated wire thicknesses, or the type of configuration. In conclusion, our preliminary study showed that the hemodynamic effect of suprarenal stent wires in patients with AAA treated with suprarenal stent grafts is dependent on the number and type of configuration of stent wire crossing the renal artery ostium. Research findings in our study are considered useful for follow-up of patients treated with suprarenal stent grafts to ensure long-term sa
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- 2009
19. Multislice CT virtual endoscopy in pre-aortic stent grafting: optimization of scanning protocols.
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Sun, Zhonghua, Chaichana, T., Jiang, W., Liu, B., Sun, Zhonghua, Chaichana, T., Jiang, W., and Liu, B.
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The purpose of this study was to investigate the optimal scanning protocols of multislice CT (MSCT) angiography in pre-aortic stent grafting, visualized on virtual endoscopy (VE). A series of scans were performed on a human aorta phantom with a 16-slice multislice CT scanner with the scanning protocols as follows: section thickness of1.0/1.5/2.0/3.0 mm, pitch value of 1.0/1.25/1.5, and reconstruction interval of 50% overlap. Signal to noise ratio and standard deviation (SD) of the signal intensity on VE images were measured to determine the image quality in relation to MSCT scanning protocols. Subjective assessment was performed by two observers evaluating the degree ofartefacts and the configuration of the renal ostium visualized on VE images. Our results showed that the scanning protocol with a section thickness of 2.0 mm resulted in the highest SNR and lowest SD compared to other protocols (p<0.05).Subjective assessment demonstrated that VE image quality was determined by section thickness, but independent of pitch values. We recommended the scanning protocol of section thickness 2.0 mm, pitch 1.5 with a reconstruction interval of 1.0 mm as the optimal one since it allows optimal visualization of VE images of aortic ostia, fewer artefacts and less radiation dose.
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- 2008
20. Edge detection of the optic disc in retinal images based on identification of a round shape
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Chaichana, T., Sun, Zhonghua, Tangjitkusolmun, S., Yoowattanna, S., Sangworasil, M., Chaichana, T., Sun, Zhonghua, Tangjitkusolmun, S., Yoowattanna, S., and Sangworasil, M.
- Abstract
This paper presents a novel method for identification of the position of the optic disc in retinal images. The method is based on the preliminary detection of the main edgedetection of retinal image. The segmentation optic disc is estimated as a circular area. We searched for areas of optic disc using Hough transform which detected several straight lines and approximated them as a circular line. The position of optic discwas identified as the center of the circle. An evaluation of the proposed procedure was performed using a set of 40 images from the DRIVE database, containing images from both healthy (33) and diseased (7) subjects. The optic disc position was correctly identified in 39 out of 40 images and the efficiency was 97.5 percent. The results illustrate that the proposed method can be used for pathological analysis of retinal images.
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- 2008
21. Simulation of blood flow in abdominal aortic aneurysms pre-and post-fenestrated stent graft repair: A preliminary study
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Heinz U Lemke, Sun, Zhonghua, Chaichana, T., Nipawan, T., Sangworasil, M., Tungjitkusolmun, S., Charoensuk, J., Phoocharoen, N., Allen, Yvonne, Hartley, D., Lawrence-Brown, Michael, Heinz U Lemke, Sun, Zhonghua, Chaichana, T., Nipawan, T., Sangworasil, M., Tungjitkusolmun, S., Charoensuk, J., Phoocharoen, N., Allen, Yvonne, Hartley, D., and Lawrence-Brown, Michael
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- 2008
22. Computer simulation and analysis of hemodynamic changes in abdominal aortic aneurysms treated with fenestrated endovascular grafts
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Sun, Zhonghua, Chaichana, T., Sangworasil, M., Allen, Yvonne, Hartley, D., Lawrence-Brown, M., Sun, Zhonghua, Chaichana, T., Sangworasil, M., Allen, Yvonne, Hartley, D., and Lawrence-Brown, M.
- Abstract
The purpose of this study was to perform a simulation of blood flow and analyze the hemodynamic changes in patients with abdominal aortic aneurysms (AAA) treated with fenestrated stent grafts. Four patients with AAA undergoing multislice computed tomography angiography pre-and post-fenestrated stent graft implantation were selected for inclusion in the study. Geometric models and hexahedral volume meshes were successfully generated for pre- and post-stent fenestrated implantation. The blood flow pattern was simulated inside the abdominal aortic aneurysm and arterial branches, as well as with a stentgraft in situ. Flow visualization showed that flow disturbances inside the aneurysm were apparently decreased and flow rate was not affected significantly at the renal arteries after deployment of the fenestrated stents intothese branches. The wall pressure was found to reduce inside the aneurysm sac following implantation of stent grafts. In this preliminary study, we successfully simulated the flow characteristics in abdominal aortic aneurysm before and after fenestrated endovascular repair.
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- 2008
23. Effect of fenestrated stents on the renal arteries: Investigation of hemodynamic changes in abdominal aortic aneurysms treated with fenestrated endovascular grafts.
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Sun, Zhonghua, Chaichana, T., Sangworasil, M., Allen, Yvonne, Hartley, D., Lawrence-Brown, M., Sun, Zhonghua, Chaichana, T., Sangworasil, M., Allen, Yvonne, Hartley, D., and Lawrence-Brown, M.
- Abstract
This article uses a novel method of combining 3D image visualization and computational fluid dynamics to investigate the potential effect of fenestrated stents on the renal arteries in terms of blood flow pattern, flow rate at different cardiac cycles, based on patients with abdominal aortic aneurysm treated with fenestrated stent grafts. 3D imaging appearance of the fenestrated stents inserted into the renal arteries is used to guide the simulation of the stent protrusion into the abdominal aorta model for analysis of hemodynamic changes. A circular stent protrusion with a length of between 5-7 mm inside the abdominal aorta is simulated in two aorta models, and computational fluid dynamics is performed to detect the change of flow pattern and flow rate at the renal arteries. Our results demonstrate change of the renal flow rate is minimal following implantation of fenestrated stents, indicating the safety of fenestrated stent graft repair of patients with aortic aneurysms.
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- 2008
24. Simulation of blood flow in abdominal aortic aneurysms treated with suprarenal and fenestrated stent grafts
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Quencer, Robert M., Sun, Zhonghua, Chaichana, T., Sangworasil, M., Quencer, Robert M., Sun, Zhonghua, Chaichana, T., and Sangworasil, M.
- Abstract
The purpose of this study was to simulate the blood flow features in patients with abdominal aortic aneurysms treated with suprarenal and fenestrated stent grafts, which are two commonly used endovascular techniques to deal with complicated aneurysm necks.
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- 2008
25. P6 IDENTIFICATION AND CHARACTERIZATION OF CORONARY PLAQUES WITH CT VIRTUAL INTRAVASCULAR ENDOSCOPY: A PICTORIAL REVIEW
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Chaichana, T., primary and Sun, Z., additional
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- 2010
- Full Text
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26. Plaque Formation at the Left Coronary Artery: Analysis of the Relationship between Arterial Angulations and Hemodynamics
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Chaichana, T., primary, Sun, Z., additional, Wong, K.K.L., additional, and Tu, J., additional
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- 2010
- Full Text
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27. Flow simulation in coronary artery models: An investigation of the effect of variable angulations at the left coronary artery.
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Chaichana, T., Zhonghua Sun, Tungjitkusolmun, S., and Sangworasil, M.
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- 2010
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28. Analysis on intra-aneurysmal flow influence by stenting.
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Wong, K.K.L., Thavornpattanapong, P., Jiyuan Tu, Chaichana, T., and Zhonghua Sun
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- 2010
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29. Haemodynamic Effect of Coronary Angulations on Subsequent Development of Coronary Artery Disease: A Preliminary Study.
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Chaichana, T., Zhonghua Sun, and Jewkes, J.
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- 2010
- Full Text
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30. Hemodynamic Effect of Calcified Plaque on Blood Flow in Carotid Artery Disease: A Preliminary Study.
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Zhonghua Sun, Mwipatayi, B., Chaichana, T., and Ng, C.
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- 2009
- Full Text
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31. 3D Virtual Intravascular Endoscopy Visualization of Coronary Artery Plaques.
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Zhonghua Sun, Chaichana, T., Dimpudus, F.J., Adipranoto, J.D., and Nugroho, J.
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- 2009
- Full Text
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32. Effect of fenestrated stents on the renal arteries: Investigation of hemodynamic changes in abdominal aortic aneurysms treated with fenestrated endovascular grafts.
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Zhonghua Sun, Chaichana, T., Tangjitkusolmun, S., Sangwatthana, S., Allen, Y.B., Hartley, D.E., Lawrence-Brown, M., and Sangworasil, M.
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- 2008
- Full Text
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33. Investigation of the hemodynamic effect of stent wires on renal arteries in patients with abdominal aortic aneurysms treated with suprarenal stent-grafts.
- Author
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Sun Z, Chaichana T, Sun, Zhonghua, and Chaichana, Thanapong
- Abstract
The purpose of the study was to investigate the hemodynamic effect of stent struts (wires) on renal arteries in patients with abdominal aortic aneurysms (AAAs) treated with suprarenal stent-grafts. Two sample patients with AAA undergoing multislice CT angiography pre- and postsuprarenal fixation of stent-grafts were selected for inclusion in the study. Eight juxtarenal models focusing on the renal arteries were generated from the multislice CT datasets. Four types of configurations of stent wires crossing the renal artery ostium were simulated in the segmented aorta models: a single wire crossing centrally, a single wire crossing peripherally, a V-shaped wire crossing centrally, and multiple wires crossing peripherally. The blood flow pattern, flow velocity, wall pressure, and wall shear stress at the renal arteries pre- and post-stent-grafting were analyzed and compared using a two-way fluid structure interaction analysis. The stent wire thickness was simulated with a diameter of 0.4, 1.0, and 2.0 mm, and hemodynamic analysis was performed at different cardiac cycles. The interference of stent wires with renal blood flow was mainly determined by the thickness of stent wires and the type of configuration of stent wires crossing the renal ostium. The flow velocity was reduced by 20-30% in most of the situations when the stent wire thickness increased to 1.0 and 2.0 mm. Of the four types of configuration, the single wire crossing centrally resulted in the highest reduction of flow velocity, ranging from 21% to 28.9% among three different wire thicknesses. Wall shear stress was also dependent on the wire thickness, which decreased significantly when the wire thickness reached 1.0 and 2.0 mm. In conclusion, our preliminary study showed that the hemodynamic effect of suprarenal stent wires in patients with AAA treated with suprarenal stent-grafts was determined by the thickness of suprarenal stent wires. Research findings in our study are useful for follow-up of patients treated with suprarenal stent-grafts to ensure long-term safety of the suprarenal fixation. [ABSTRACT FROM AUTHOR]
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- 2009
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34. An Approach to Determine the Weibull Parameters and Wind Power Analysis of Saint Martin’s Island, Bangladesh
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Islam Khandaker Dahirul, Dussadee Natthawud, and Chaichana Tanate
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Engineering (General). Civil engineering (General) ,TA1-2040 - Abstract
This paper explores wind speed distribution using Weibull probability distribution and Rayleigh distribution methods that are proven to provide accurate and efficient estimation of energy output in terms of wind energy conversion systems. Two parameters of Weibull (shape and scale parameters k and c respectively) and scale parameter of Rayleigh distribution have been determined based on hourly time-series wind speed data recorded from October 2014 to October 2015 at Saint Martin’s island, Bangladesh. This research has been carried out to examine three numerical methods namely Graphical Method (GM), Empirical Method (EM), Energy Pattern Factor method (EPF) to estimate Weibull parameters. Also, Rayleigh distribution method has been analyzed throughout the study. The results in the research revealed that the Graphical method followed by Empirical method and Energy Pattern Factor method were the most accurate and efficient way for determining the value of k and c to approximate wind speed distribution in terms of estimating power error. Rayleigh distribution gives the most power error in the research. Potential for wind energy development in Saint Martin’s island, Bangladesh as found from the data analysis has been explained in this paper.
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- 2016
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35. Development of local food growth logistics and economics
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Chaichana, T, Brennan, CS, Osiriphun, S, Thongchai, P, and Wangtueai, S
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36. Data from a survey of coffee cultivation in lowland and highland areas to support agriculture during climate change.
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Chaichana T, Reeve G, Piboonrungroj P, Muangprathub J, Kunno J, Robson MG, and Drury B
- Abstract
This survey aimed to acquire and generate significant information on coffee cultivation in high and low elevations to support agriculture during climate change. This survey dataset helps understand coffee cultivation in highland and lowland areas with diverse climates and environmental conditions for coffee researchers to use this data to improve cultivation and production techniques. In the business scope, this dataset provides a critical vision on the value proposition of the coffee business to maintain conservation and wealth creation of the coffee chain. Similarly, coffee chains can use this data as an example to assess sustainability and carbon literacy. The structured interviews and field trips were conducted at coffee plantations in southern and northern Thailand. The transcript results were manually coded for thematic analysis. This dataset offers insights into anthropogenic plant migration and plant distribution for researchers and academics to use as a valuable resource and good reference in agricultural and biodiversity research. Today, agriculture faces many challenges, such as climate change, water shortage, and improper land management. This information on coffee cultivation at high and low altitudes may help others grow crops in ever-changing climates., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper. The generative AI writing app is not used for writing., (© 2024 The Author(s).)
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- 2024
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37. Catabolic mediators from TLR2-mediated proteoglycan aggrecan peptide-stimulated chondrocytes are reduced by Lactobacillus-conditioned media.
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Sengprasert P, Waitayangkoon P, Kamenkit O, Sawatpanich A, Chaichana T, Wongphoom J, Ngarmukos S, Taweevisit M, Lotinun S, Tumwasorn S, Tanavalee A, and Reantragoon R
- Subjects
- Humans, Culture Media, Conditioned pharmacology, Signal Transduction drug effects, Osteoarthritis metabolism, Osteoarthritis pathology, Cells, Cultured, ADAMTS4 Protein metabolism, STAT3 Transcription Factor metabolism, Peptides pharmacology, Peptides metabolism, Proteoglycans metabolism, Proteoglycans pharmacology, Matrix Metalloproteinase 1 metabolism, Matrix Metalloproteinase 1 genetics, NF-KappaB Inhibitor alpha metabolism, Chondrocytes metabolism, Chondrocytes drug effects, Toll-Like Receptor 2 metabolism, Aggrecans metabolism, Lactobacillus metabolism
- Abstract
In osteoarthritis (OA), extracellular matrix (ECM) digestion by cartilage-degrading enzymes drives cartilage destruction and generates ECM fragments, such as proteoglycan aggrecan (PG) peptides. PG peptides have been shown to induce immunological functions of chondrocytes. However, the role of PG peptides in stimulating catabolic mediators from chondrocytes has not been investigated. Therefore, we aim to determine the effects and its mechanism by which PG peptides induce chondrocytes to produce catabolic mediators in OA. Human chondrocytes were stimulated with IFNγ and various PG peptides either (i) with or (ii) without TLR2 blockade or (iii) with Lactobacillus species-conditioned medium (LCM), a genus of bacteria with anti-inflammatory properties. Transcriptomic analysis, cartilage-degrading enzyme production and TLR2-intracellular signaling activation were investigated. Chondrocytes treated with PG peptides p16-31 and p263-280 increased expression levels of genes associated with chondrocyte hypertrophy, cartilage degradation and proteolytic enzyme production. TLR2 downstream signaling proteins (STAT3, IkBα and MAPK9) were significantly phosphorylated in p263-280 peptide-stimulated chondrocytes. MMP-1 and ADAMTS-4 were significantly reduced in p263-280 peptides-treated condition with TLR2 blockade or LCM treatment. Phosphorylation levels of IkBa, ERK1/2 and MAPK9 were significantly decreased with TLR2 blockade, but only phosphorylation levels of MAPK9 was significantly decreased with LCM treatment. Our study showed that PG peptide stimulation via TLR2 induced cartilage-degrading enzyme production via activation of MAPK, NFκB and STAT3 pathways., (© 2024. The Author(s).)
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- 2024
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38. Modelling and assessing new SME digital business status for visualising virtual economics and sustainability economic indicators: Empirical evidence from poultry business.
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Chaichana T, Reeve G, Jaisan C, and Chakrabandhu Y
- Abstract
SMEs are generally recognised as financial contributors to regional economic development. Despite the enormous contributions of digital SMEs to sustainable economic growth and regional development have not yet been reported. This paper assesses and models SME businesses to gain a digital business status and model. These days, visualising economic growth is challenging and powerful to identify business performance and realise sustainable regional development. This research analyses empirical data obtained from a poultry business to form a standard model for implementing a new SME digital business model and status. This standard model is a guideline to measure the other SME businesses and productions. Localisation of the SDGs was analysed using thematic analysis. Mathematical computation is used to visualise virtual economic growth geographically. Hence, our digital business model and status demonstrated business performance, management, and economic growth., Competing Interests: The authors declare the following financial interests/personal relationships which may be considered as potential competing interests:The authors declare no conflict of interest, no personal relationships, and no financial interests that have influenced the research reported in this paper., (© 2024 The Authors. Published by Elsevier Ltd.)
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- 2024
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39. Infrapatellar fat pad adipose tissue-derived macrophages display a predominant CD11c+CD206+ phenotype and express genotypes attributable to key features of OA pathogenesis.
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Hengtrakool P, Leearamwat N, Sengprasert P, Wongphoom J, Chaichana T, Taweevisit M, Ngarmukos S, Tanavalee A, Palaga T, and Reantragoon R
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- Humans, Culture Media, Conditioned, Macrophages pathology, Phenotype, Genotype, Adipose Tissue pathology, Osteoarthritis, Knee genetics, Osteoarthritis, Knee pathology
- Abstract
Objectives: In knee osteoarthritis (OA), macrophages are the most predominant immune cells that infiltrate synovial tissues and infrapatellar fat pads (IPFPs). Both M1 and M2 macrophages have been described, but their role in OA has not been fully investigated. Therefore, we investigated macrophage subpopulations in IPFPs and synovial tissues of knee OA patients and their correlation with disease severity, examined their transcriptomics, and tested for factors that influenced their polarization., Methods: Synovial tissues and IPFPs were obtained from knee OA patients undergoing total knee arthroplasty. Macrophages isolated from these joint tissues were characterized via flow cytometry. Transcriptomic profiling of each macrophage subpopulations was performed using NanoString technology. Peripheral blood monocyte-derived macrophages (MDMs) were treated with synovial fluid and synovial tissue- and IPFP-conditioned media. Synovial fluid-treated MDMs were treated with platelet-rich plasma (PRP) and its effects on macrophage polarization were observed., Results: Our findings show that CD11c+CD206+ macrophages were predominant in IPFPs and synovial tissues compared to other macrophage subpopulations (CD11c+CD206-, CD11c-CD206+, and CD11c-CD206- macrophages) of knee OA patients. The abundance of macrophages in IPFPs reflected those in synovial tissues but did not correlate with disease severity as determined from Mankin scoring of cartilage destruction. Our transcriptomics data demonstrated highly expressed genes that were related to OA pathogenesis in CD11c+CD206+ macrophages than CD11c+CD206-, CD11c-CD206+, and CD11c-CD206- macrophages. In addition, MDMs treated with synovial fluid, synovial tissue-conditioned media, or IPFP-conditioned media resulted in different polarization profiles of MDMs. IPFP-conditioned media induced increases in CD86+CD206+ MDMs, whereas synovial tissue-conditioned media induced increases in CD86+CD206- MDMs. Synovial fluid treatment (at 1:8 dilution) induced a very subtle polarization in each macrophage subpopulation. PRP was able to shift macrophage subpopulations and partially reverse the profiles of synovial fluid-treated MDMs., Conclusion: Our study provides an insight on the phenotypes and genotypes of macrophages found in IPFPs and synovial tissues of knee OA patients. We also show that the microenvironment plays a role in driving macrophages to polarize differently and shifting macrophage profiles can be reversed by PRP., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2024 Hengtrakool, Leearamwat, Sengprasert, Wongphoom, Chaichana, Taweevisit, Ngarmukos, Tanavalee, Palaga and Reantragoon.)
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- 2024
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40. Histological features of knee osteoarthritis treated with triamcinolone acetonide and hyaluronic acid.
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Charnwichai P, Tammachote R, Tammachote N, Chaichana T, and Kitkumthorn N
- Abstract
Osteoarthritis (OA) is one of the most common degenerative joint diseases leading to disability in the end stage. Although intra-articular triamcinolone acetonide (TA) is one of the OA treatments that have been widely used, the side effects of such corticosteroids are still controversial. Intra-articular hyaluronic acid (HA) injection is another therapeutic option for patients with OA who do not want to use corticosteroids because of their side effects. However, the difference between the histological features associated with TA and HA in the treatment of OA remains unclear. Thus, the present study aimed to compare the histological effects of TA and HA on the cartilage of patients with knee OA. In the current study, 31 patients diagnosed with grade 3-4 knee OA on the Kellgren-Lawrence radiographic grading scale were separated into three groups: TA (n=12); HA (n=7) and untreated group (n=12). Histological examination of the whole articular cartilages of the patients was performed with hematoxylin and eosin and Alcian staining, as well as using a TUNEL assay. Clinical data such as cartilage thickness, structural and component deterioration, proteoglycan levels, apoptosis and empty lacunae were compared between the three groups. The results showed a high level of deterioration in both TA and HA groups but not in the untreated group, although the thickness of cartilage in the HA group was lower compared with that in the TA and untreated groups. The proteoglycan levels in the TA group were lower compared with those in the HA group. Moreover, the number of empty lacunae in the HA group was higher compared with that in the TA group, while no difference in apoptosis was found between TA and HA groups. A significant difference was not found in the histological staining between TA and HA groups. On the other hand, a significant difference was found in cartilage deterioration between the medial and lateral sides in these groups. TA and HA groups showed comparable histological results. TA injection is cheaper and easier but has more adverse effects for patients with knee OA than HA injection. Therefore, orthopaedists should select TA or HA based on the economic and specific needs of patients., Competing Interests: The authors declare that they have no competing interests., (Copyright: © Charnwichai et al.)
- Published
- 2023
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41. Reliability of Upright Chest Radiography as a Diagnostic Screening Tool for Acromioclavicular Joint Dislocations.
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Chaichana T, Apivatgaroon A, Rujiraphum P, Sanguanjit P, and Chernchujit B
- Abstract
Background: The standard radiographic view for diagnosing acromioclavicular joint (ACJ) dislocations is the Zanca view of both shoulders to assess superior displacement of the distal clavicle by measuring the coracoclavicular distance (CCD) and comparing it with the uninjured shoulder; however, there is no consensus on a gold standard for diagnostic measures to classify acute ACJ injuries., Purpose: To compare the CCD from an upright chest radiograph with a standard Zanca view of both shoulders in patients with an ACJ dislocation., Study Design: Cohort study (diagnosis); Level of evidence, 3., Methods: We reviewed the records of 70 patients with an ACJ dislocation between 2010 and 2021 who had both an upright chest radiograph and a Zanca view. An ACJ dislocation was classified as low grade (Rockwood types 1-3) or high grade (Rockwood type 5). The CCD was measured on the upright chest radiograph and the Zanca view by 2 independent reviewers, and the percentage of the CCD difference compared with the unaffected side (ΔCCD) was calculated and compared between the upright chest radiograph and the Zanca view. Interrater and intrarater reliability were determined using the intraclass correlation coefficient., Results: Included were 70 patients (55 male and 15 female; mean age, 46 years). There were 29 patients (41.43%) with a low-grade injury and 41 patients (58.57%) with a high-grade injury. In the overall analysis, the ΔCCD on the upright chest radiograph and Zanca view was significantly different (130.25% ± 88.42% vs 152.69% ± 106.56%, respectively; mean difference, 22.44% [95% CI, 2.40% to 42.48%]; P = .029). The subgroup analysis revealed that the ΔCCD on the upright chest radiograph and Zanca view was significantly different for patients with a low-grade injury (60.71% ± 25.79% vs 91.46% ± 68.54%, respectively; mean difference, 30.76% [95% CI, 7.18% to 54.33%]; P = .012) but not different for patients with a high-grade injury (179.45% ± 83.87% vs 196.00% ± 107.97%, respectively; mean difference, 16.56% [95% CI, -14.06% to 47.18%]; P = .281). The intraclass correlation coefficients for the ΔCCD measurements indicated good to excellent interrater and intrarater reliability., Conclusion: The study findings indicated that upright chest radiography can be used as a diagnostic screening tool for high-grade ACJ dislocations, but not for low-grade ACJ injuries, compared with the Zanca view., Competing Interests: The authors declared that there are no conflicts of interest in the authorship and publication of this contribution. AOSSM checks author disclosures against the Open Payments Database (OPD). AOSSM has not conducted an independent investigation on the OPD and disclaims any liability or responsibility relating thereto., (© The Author(s) 2023.)
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- 2023
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42. BRAF V600E mutation in pediatric intracranial and cranial juvenile xanthogranuloma.
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Techavichit P, Sosothikul D, Chaichana T, Teerapakpinyo C, Thorner PS, and Shuangshoti S
- Subjects
- Brain Diseases enzymology, Brain Diseases pathology, Brain Diseases therapy, Child, Child, Preschool, DNA Mutational Analysis, Erdheim-Chester Disease enzymology, Erdheim-Chester Disease pathology, Erdheim-Chester Disease therapy, Genetic Markers, Genetic Predisposition to Disease, Humans, Immunohistochemistry, Magnetic Resonance Imaging, Male, Phenotype, Treatment Outcome, Xanthogranuloma, Juvenile enzymology, Xanthogranuloma, Juvenile pathology, Xanthogranuloma, Juvenile therapy, Brain Diseases genetics, Erdheim-Chester Disease genetics, Mutation, Proto-Oncogene Proteins B-raf genetics, Xanthogranuloma, Juvenile genetics
- Abstract
Juvenile xanthogranuloma (JXG) is a cutaneous form of non-Langerhans cell histiocytosis, primarily affecting children. The lesion is presumed to originate from either macrophages or dermal dendritic cells. JXG can rarely present as an isolated intracranial lesion and, in contrast to the dismal outcome of patients with systemic disease, cranial JXG has been shown to carry a more favorable prognosis. Here, we report for the first time 3 pediatric cases of JXG with a BRAF V600E mutation, 2 with intracranial lesions and 1 with cranial lesions. Although these intracranial/cranial lesions have been referred to as JXG, they likely differ from cutaneous JXG in both the clinical features and BRAF status. It may be more appropriate to classify intracranial/cranial JXG in the same group as Langerhans cell histiocytosis and Erdheim-Chester disease, which also have a BRAF V600E mutation. Further study of BRAF status in a larger series of JXG is warranted., (Copyright © 2017 Elsevier Inc. All rights reserved.)
- Published
- 2017
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43. An investigation of correlation between left coronary bifurcation angle and hemodynamic changes in coronary stenosis by coronary computed tomography angiography-derived computational fluid dynamics.
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Sun Z and Chaichana T
- Abstract
Background: To investigate the correlation between left coronary bifurcation angle and coronary stenosis as assessed by coronary computed tomography angiography (CCTA)-generated computational fluid dynamics (CFD) analysis when compared to the CCTA analysis of coronary lumen stenosis and plaque lesion length with invasive coronary angiography (ICA) as the reference method., Methods: Thirty patients (22 males, mean age: 59±6.9 years) with calcified plaques at the left coronary artery were included in the study with all patients undergoing CCTA and ICA examinations. CFD simulation was performed to analyze hemodynamic changes to the left coronary artery models in terms of wall shear stress, wall pressure and flow velocity, with findings correlated to the coronary stenosis and degree of bifurcation angle. Calcified plaque length was measured in the left coronary artery with diagnostic value compared to that from coronary lumen and bifurcation angle assessments., Results: Of 26 significant stenosis at left anterior descending (LAD) and 13 at left circumflex (LCx) on CCTA, only 14 and 5 of them were confirmed to be >50% stenosis at LAD and LCx respectively on ICA, resulting in sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of 100%, 52%, 49% and 100%. The mean plaque length was measured 5.3±3.6 and 4.4±1.9 mm at LAD and LCx, respectively, with diagnostic sensitivity, specificity, PPV and NPV being 92.8%, 46.7%, 61.9% and 87.5% for extensively calcified plaques. The mean bifurcation angle was measured 83.9±13.6º and 83.8±13.3º on CCTA and ICA, respectively, with no significant difference (P=0.98). The corresponding sensitivity, specificity, PPV and NPV were 100%, 78.6%, 84.2% and 100% based on bifurcation angle measurement on CCTA, 100%, 73.3%, 78.9% and 100% based on bifurcation angle measurements on ICA, respectively. Wall shear stress was noted to increase in the LAD and LCx models with significant stenosis and wider angulation (>80º), but demonstrated little or no change in most of the coronary models with no significant stenosis and narrower angulation (<80º)., Conclusions: This study further clarifies the relationship between left coronary bifurcation angle and significant stenosis, with angulation measurement serving as a more accurate approach than coronary lumen assessment or plaque lesion length for determining significant coronary stenosis. Left coronary bifurcation angle is suggested to be incorporated into coronary artery disease (CAD) assessment when diagnosing significant CAD., Competing Interests: Conflicts of Interest: The authors have no conflicts of interest to declare.
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- 2017
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44. A systematic review of computational fluid dynamics in type B aortic dissection.
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Sun Z and Chaichana T
- Subjects
- Aortic Dissection diagnosis, Aortic Aneurysm, Thoracic diagnosis, Computational Biology methods, Humans, Shear Strength physiology, Aortic Dissection physiopathology, Aortic Aneurysm, Thoracic physiopathology, Blood Flow Velocity physiology, Hydrodynamics
- Published
- 2016
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45. Impact of plaques in the left coronary artery on wall shear stress and pressure gradient in coronary side branches.
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Chaichana T, Sun Z, and Jewkes J
- Subjects
- Aortography, Computer Simulation, Coronary Artery Disease diagnostic imaging, Coronary Vessels diagnostic imaging, Hemodynamics, Humans, Hydrodynamics, Male, Middle Aged, Models, Cardiovascular, Plaque, Atherosclerotic diagnostic imaging, Pressure, Shear Strength, Stress, Mechanical, Coronary Artery Disease physiopathology, Coronary Vessels physiopathology, Plaque, Atherosclerotic physiopathology
- Abstract
In this study, we investigate plaques located at the left coronary bifurcation. We focus on the effect that the resulting changes in wall shear stress (WSS) and wall pressure stress gradient (WPSG) have on atherosclerotic progress in coronary artery disease. Coronary plaques were simulated and placed at the left main stem and the left anterior descending to produce >50% narrowing of the coronary lumen. Computational fluid dynamics analysis was carried out, simulating realistic physiological conditions that show the in vivo cardiac haemodynamic. WSS and WPSG in the left coronary artery were calculated and compared in the left coronary models, with and without the presence of plaques during cardiac cycles. Our results showed that WSS decreased while WPSG was increased in coronary side branches due to the presence of plaques. There is a direct correlation between coronary plaques and subsequent WSS and WPSG variations based on the bifurcation plaques simulated in the realistic coronary models.
- Published
- 2014
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46. Hemodynamic impacts of various types of stenosis in the left coronary artery bifurcation: a patient-specific analysis.
- Author
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Chaichana T, Sun Z, and Jewkes J
- Subjects
- Adult, Aged, Coronary Angiography, Coronary Stenosis diagnostic imaging, Coronary Vessels diagnostic imaging, Female, Humans, Male, Middle Aged, Precision Medicine, Shear Strength, Stress, Mechanical, Coronary Stenosis physiopathology, Coronary Vessels physiopathology, Hemodynamics
- Abstract
This study investigates the hemodynamic changes to various types of coronary stenosis in the left coronary artery bifurcation, based on a patient-specific analysis. Twenty two patients with left coronary artery disease were included in this study. All stenoses involving the left coronary artery bifurcation were classified into four types, according to their locations: A) left circumflex (LCx) and left anterior descending (LAD), B) LCx only, C) left main stem only, and D) LAD only. Computational fluid dynamics (CFD) was performed to analyze the flow and wall shear stress (WSS) changes in all reconstructed left coronary geometries. Our results showed that the flow velocity and WSS were significantly increased at stenotic locations. High WSS was found at >70% lumen stenosis, which ranged from 2.5 Pa to 3.5 Pa. This study demonstrates that in patients with more than 50% stenosis in the left coronary artery bifurcation, WSS plays an important role in providing information about the extent of coronary atherosclerosis in the left coronary artery branch., (Copyright © 2013 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. All rights reserved.)
- Published
- 2013
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47. Haemodynamic analysis of the effect of different types of plaques in the left coronary artery.
- Author
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Chaichana T, Sun Z, and Jewkes J
- Subjects
- Blood Flow Velocity, Blood Pressure, Computer Simulation, Coronary Angiography methods, Humans, Male, Middle Aged, Coronary Artery Disease diagnostic imaging, Coronary Artery Disease physiopathology, Coronary Circulation, Coronary Vessels physiopathology, Models, Cardiovascular, Radiographic Image Interpretation, Computer-Assisted methods, Tomography, X-Ray Computed methods
- Abstract
Purpose: Coronary plaque has been shown to directly affect the blood parameters, however, haemodynamic variations based on the plaque configuration has not been studied. In this study we investigate the haemodynamic effects of various types of plaques in the left coronary bifurcation., Methods: Eight types of plaque configurations were simulated and located in various positions in the left main stem, the left anterior descending and left circumflex to produce a >50% narrowing of the coronary lumen. We analyse and characterise haemodynamic effects caused by each type of plaque. Computational fluid dynamics was performed to simulate realistic physiological conditions that reveal the in vivo cardiac haemodynamics. Velocity, wall shear stress (WSS) and pressure gradient (PSG) in the left coronary artery were calculated and compared in all plaque configurations during cardiac cycles., Results: Our results showed that the highest velocity and PSG were found in the type of plaque configuration which involved all of the three left coronary branches. Plaques located in the left circumflex branch resulted in highly significant changes of the velocity, WSS and PSG (p<0.001) when compared to the other types of plaque configurations., Conclusion: Our analysis provides an insight into the distribution of plaque at the left bifurcation, and corresponding haemodynamic effects, thus, improving our understanding of atherosclerosis., (Copyright © 2013 Elsevier Ltd. All rights reserved.)
- Published
- 2013
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48. Hemodynamic impacts of left coronary stenosis: a patient-specific analysis.
- Author
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Chaichana T, Sun Z, and Jewkes J
- Subjects
- Blood Flow Velocity, Coronary Stenosis diagnostic imaging, Coronary Vessels diagnostic imaging, Coronary Vessels physiopathology, Female, Humans, Image Processing, Computer-Assisted, Male, Middle Aged, Stress, Mechanical, Tomography, X-Ray Computed, Coronary Stenosis physiopathology, Hemodynamics physiology
- Abstract
This study analyses the hemodynamic variations surrounding stenoses located at the left coronary bifurcation, and their influence on the wall shear stress (WSS) in realistic coronary geometries. Four patients with suspected coronary artery disease were chosen, and coronary models were reconstructed based on high-resolution CT data. The coronary stenoses were observed at the left circumflex and left anterior descending branches, resulting in a lumen narrowing of >50%. Flow analysis was performed using computational fluid dynamics, to simulate the cardiac flow conditions of the realistic individual patient geometry. Blood flow and WSS changes in the left coronary artery were calculated throughout the entire cardiac phases. Our results revealed that the recirculation regions were found at the poststenotic locations. WSS was found to increase at the stenotic positions in all four patients. There is a strong correlation between coronary stenosis and the hemodynamic changes, which are reflected in blood flow pattern and WSS, based on the realistic left coronary geometries.
- Published
- 2013
49. Investigation of the haemodynamic environment of bifurcation plaques within the left coronary artery in realistic patient models based on CT images.
- Author
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Chaichana T, Sun Z, and Jewkes J
- Subjects
- Blood Flow Velocity, Blood Pressure, Computer Simulation, Coronary Angiography, Coronary Artery Disease diagnostic imaging, Humans, Middle Aged, Shear Strength, Coronary Artery Disease physiopathology, Coronary Circulation, Coronary Vessels physiopathology, Models, Cardiovascular
- Abstract
The aim of this study was to investigate the plaques at the left coronary artery (LCA) and their effect on the haemodynamic and wall shear stress (WSS) in realistic patient models. Three sample patients with left coronary disease were selected based on CT data. The plaques were present at the left anterior descending and left circumflex branches with more than 50 % lumen narrowing. Computational fluid dynamics analysis was used to perform simulation of patient-specific models with realistic physiological conditions that demonstrate in vivo cardiac flow. WSS and blood flow in the LCA were measured during cardiac cycles. Our results showed that WSS was found to increase at the stenotic locations and decrease at pre- and post-plaque locations, whilst the recirculation location was found at post-plaque regions. There is a strong correlation between coronary bifurcation plaques and hemodynamic and WSS changes, based on the realistic coronary disease models.
- Published
- 2012
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50. Computational fluid dynamics analysis of the effect of plaques in the left coronary artery.
- Author
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Chaichana T, Sun Z, and Jewkes J
- Subjects
- Computer Simulation, Coronary Circulation physiology, Coronary Stenosis physiopathology, Humans, Coronary Vessels physiopathology, Hemodynamics physiology, Hydrodynamics, Models, Cardiovascular, Plaque, Atherosclerotic physiopathology
- Abstract
This study was to investigate the hemodynamic effect of simulated plaques in left coronary artery models, which were generated from a sample patient's data. Plaques were simulated and placed at the left main stem and the left anterior descending (LAD) to produce at least 60% coronary stenosis. Computational fluid dynamics analysis was performed to simulate realistic physiological conditions that reflect the in vivo cardiac hemodynamics, and comparison of wall shear stress (WSS) between Newtonian and non-Newtonian fluid models was performed. The pressure gradient (PSG) and flow velocities in the left coronary artery were measured and compared in the left coronary models with and without presence of plaques during cardiac cycle. Our results showed that the highest PSG was observed in stenotic regions caused by the plaques. Low flow velocity areas were found at postplaque locations in the left circumflex, LAD, and bifurcation. WSS at the stenotic locations was similar between the non-Newtonian and Newtonian models although some more details were observed with non-Newtonian model. There is a direct correlation between coronary plaques and subsequent hemodynamic changes, based on the simulation of plaques in the realistic coronary models.
- Published
- 2012
- Full Text
- View/download PDF
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