KMITL

Permanent URI for this communityhttps://dspace.kmitl.ac.th/handle/123456789/1

Browse

Search Results

Now showing 1 - 6 of 6

Some of the metrics are blocked by your
consent settings
Flow simulation in coronary artery models: An investigation of the effect of variable angulations at the left coronary artery
(2010-12-01)
Chaichana, Thanapong
;
Sun, Zhonghua
;
Tungjitkusolmun, Supan
;
Sangworasil, Manas
This study was designed to investigate the hemodynamics in the left coronary artery with the aim of identifying the relationship between angulations of left coronary bifurcation and development of atherosclerosis. Six 3D left coronary models were simulated for computational fluid dynamic analysis. The left coronary model was composed of left main stem, left anterior descending and left circumflex branches. The angulations at the left bifurcation were simulated with angles ranging from 90°, 75°, 60°, 45°, 30° to 15°. The computational fluid dynamic was used for analysis of flow velocity, wall pressure and wall shear stress. Our results showed that apparent low shear stress and high wall pressure was noticed at the left coronary bifurcation regions with wide angled models. Flow pattern was also changed with angled becoming wide in the simulated models. Our analysis shows direction relationship between coronary angulation and development of atherosclerosis. Future studies are required to perform computational fluid dynamic analysis in coronary models from patients' data with different degree of coronary stenosis. © 2010 IEEE.
Some of the metrics are blocked by your
consent settings
Hemodynamic effect of calcifed plaque on blood flow in carotid artery disease: A preliminary study - Hemodynamic effect of calcified plaque
(2009-12-31)
Sun, Zhonghua
;
Mwipatayi, Bibombe
;
Chaichana, Thanapong
;
Ng, Curtise
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.
Some of the metrics are blocked by your
consent settings
Investigation of hemodynamic changes in abdominal aortic aneurysms treated with fenestrated endovascular grafts
(2009-12-01)
Sun, Zhonghua
;
Chaichana, Thanapong
;
Allen, Yvonne B.
;
Sangworasil, Manas
;
Tungjitkusolmun, Supan
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.
Some of the metrics are blocked by your
consent settings
Computational fluid analysis of blood flow characteristics in abdominal aortic aneurysms treated with suprarenal endovascular grafts
(2009-12-01)
Sun, Zhonghua
;
Chaichana, Thanapong
;
Sangworasil, Manas
;
Tungjitkusolmun, Supan
The purpose of this study is to investigate the hemodynamic effects of suprarenal stent grafts on the renal arteries in the treatment of patients with abdominal aortic aneurysm. Suprarenal stent grafts have been increasingly used for treatment of aortic aneurysms with suboptimal aneurysm necks. However, the long-term safety of this procedure is yet to be determined. 2 sample patients undergoing suprarenal stent grafting were included in the study. Four variable configurations of stent wires crossing the renal artery ostium were simulated in aorta models based on CT generated data, at different cardiac cycles. The stent wires thickness was set 0.5 mm which is similar to the actual diameter of a stent wire. Computational fluid dynamic analysis showed slightly decrease of flow velocity to the renal arteries with multiple wires crossing, and no changes of flow velocity to the renal arteries with single wire crossing. Our preliminary results demonstrated the safety of suprarenal stent grafting. Further studies are required to investigate the effect of different wire thickness on subsequent hemodynamic changes to the renal arteries.
Some of the metrics are blocked by your
consent settings
Investigation of the hemodynamic effect of stent wires on renal arteries in patients with abdominal aortic aneurysms treated with suprarenal stent-grafts
(2009-07-01)
Sun, Zhonghua
;
Chaichana, Thanapong
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. © 2009 Springer Science+Business Media, LLC.
Some of the metrics are blocked by your
consent settings
Effect of fenestrated stents on the renal arteries: Investigation of hemodynamic changes in abdominal aortic aneurysms treated with fenestrated endovascular grafts
(2008-12-01)
Sun, Zhonghua
;
Chaichana, Thanapong
;
Tangjitkusolmun, Supan
;
Sangwatthana, Surasak
;
Allen, Yvonne B.
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. © 2008 IEEE.

KMITL

Browse

Filters

Settings

Sort By

Results per page

Search Results