Research Areas > Circulatory Vascular Flows and Biomedical Imaging

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Visulization of valcular blood flow using high-frequency ultrasound

Post Image In order to investigate the blood flow around the perivalvular area in a human superficial vein using high-frequency ultrasound (HFUS) speckle image velocimetry. HFUS B-mode images were captured from the superficial veins of human lower extremity with a 35-MHz transducer. In the vicinity of the venous valve, the opening and closing motions of valve cusps were simultaneously visualized with the phasic variation of velocity fields. This measurement technique combining PIV algorithm and HFUS B-mode imaging was found to be unique and useful for investigating the hemodynamic characteristics of bloo...   내용 보기

Effect of hypothermia on hemodynamic characteristics of blood flow

Post Image  Blood in the outflow tract (OFT) of a chicken embryonic heart exhibits variable flow depending on variation of environmental conditions. The abnormal flow occurs such as back-flow and bradycardia in hypothermic condition. This results from the inharmonic heart movement under hypothermic condition and the undeveloped heart valve at this developmental stage. The comparative study on the blood flows in the OFT would be helpful to understand the corresponding hemodynamic characteristics.   Velocity fields and outflow tract images at instant to reach peak outflow and start back-flow....   내용 보기

Development of CM (contrast medium) particles for angiographic X-ray PIV system

Post Image In applying the x-ray particle image velocimetry technique (PIV) to biofluid flows, the most pivotal prerequisite is suitable flow tracing sensors which should be detected effectively by the x-ray imaging system. In this study, to design those flow tracing sensors, x-ray contrast agent Iopamidol was encapsulated into the poly(vinyl alcohol) (PVA) microparticles crosslinked by glutaraldehyde (GA).   The x-ray absorption ability of the designed tracing sensors was examined by a synchrotron x-ray imaging technique. The x-ray absorption coefficients of the particle sensors were express...   내용 보기

In-vivo meas. of blood flow in a stenosed vessel of chick embryo

Post Image Blood flow in a stenosed blood vessel is very important, because it is closely related to the outbreak of vascular circulatory diseases. To investigate the hemodynamic characteristics of blood flow in a stenosed vessel, we induced stenosis in a micro-scale vessel using laser induced thrombogenesis model.  According to this model, strong laser exposure was applied at the extraembryonic blood vessels of a chicken embryo. The result showed that red blood cells absorbed laser light energy formed stable thrombosis in a vessel and it firmly adhered in a vessel with disturbing blood flow. To an...   내용 보기

Analysis on hemodynamic characteristics of blood flow in a stenosed vessel

Post Image Atherosclerosis in arterial blood vessels is closely related to the flow characteristics of blood at stenotic vessels or bifurcated blood vessels. Thus, systematic interdisciplinary research works are needed to diagnose and analyze the circulatory vascular diseases with clinical and hemodynamic approaches. In vivo and in vitro experiments are undertaken to measure blood flows in the stenosed channel for revealing hemodynamic characteristics and better understanding on such circulatory diseases.   Figure descriptionNear the stenosed throat, the hemodynamic characteristics such as blood f...   내용 보기

Development of angiographic PIV system and clinical applications

Post Image   Abnormal blood circulation caused by recirculation flow or low shear stress is one of the main causes of circulatory diseases. Hence, quantitatively accurate information on the blood flows is required for better and earlier diagnosis of the diseases. For measuring the blood flow inside arterioles, μm-scale spatial resolution and ms temporal resolutions are required to analyze the blood flow in a hemodynamic point of view.   PIV technique has been used in flow visualization experiments. It provides quantitative flow information with a high spatial and temporal resolution. In gene...   내용 보기

Experimental analysis of blood flows in aorta abdominal aneurysm

Post Image Modification or damage of endothelium cell is closely related to shear stress around the blood vessels. The shear stress and blood circulation has been known as one of the main causes of circulatory diseases. Especially, shear stress in endothelium surface has been reported to influence aneurysm occurrence, growth and damage in the cerebral and abdominal aortic aneurysm.In this study, a transparent experimental model of abdominal aneurysm was made by using CT data of a real patient. It was connected to a pulsatile pump. The velocity field information of the blood flow in it was measured using ...   내용 보기

Fabrication of CM(contrast material) microcapsules as flow tracers for X-ray imaging

Post Image To measure the dynamic behavior of biological flows quantitatively, an X-ray PIV (particle image velocimetry) technique has been developed.To apply the x-ray PIV technique to biofluid flows, particulated form of X-ray contrast agents are inevitably required as a flow tracer. Using a cross-linked PVA (polyvinyl alcohol)microparticle, Iopamidol (iodinated X-ray contrast agentsdeveloped by Bracco which is also known as Solutrast®) was successfully encapsulated by using the water-in-oil emlusion template method.&n...   내용 보기

In vivo X-ray PIV measurement of whole blood flows in animals

Post Image Using the synchrotron X-ray PIV technique, we already measured blood flows in an opaque tube. In this study, we are trying to visualize blood flows of a rat in vivo. By advancing this kind of visualization techniques, we can visualize the real blood flows inside human body for better understanding on circulatory diseases occurring at bifurcated arteries and provide new information needed to develop medical instruments.Figure descriptionVisualization of blood flow in the mesentery of a rat   내용 보기

Experimental analysis of blood flows in embryonic avian heart and arterial blood vessels

Post Image Blood flow inside blood vessels are closely related to circulatory vascular diseases. In this study, hemodynamic characteristics of microcirculation are investigated. Then the velocity fields of the blood flows in embryonic avian heart and various blood vessels are analyzed to reveal the hemodynamic characteristics related to circulatory diseases. At the same time, by visualizing the blood flow inside the heart, the heart beating mechanism and the interactions between the nearby heart chambers as well as quantitative information on the blood flow inside the heart will be studied in detail. Mor...   내용 보기