• 한국전산유체공학회:학술대회논문집
• /
• 2008.03b
• /
• pp.6-9
• /
• 2008

Analyzing the characteristics of blood flow in the blood vessels is very important to diagnose the circulatory diseases. In order to investigate the hemodynamic characteristics in vivo, the measurements of blood flows inside the extraembryonic arterial and venous blood vessels of chicken embryos were carried out using an in vivo micro-PIV technique. The circulatory diseases are closely related with the formation of abnormal hemodynamic shear stress regions, thereby it is important to get blood velocity and vessel's morphological information according to the vessel configuration and the flow conditions. In this study, the flow images of RBCs in blood vessels were obtained using a high-speed CMOS camera with a spatial resolution of approximately 14.6${\mu}$m${\times}$14.6${\mu}$m in the whole circulation network of blood vessels. The blood flows in the veins and arteries show steady laminar and unsteady pulsatile flow characteristics, respectively. The mean blood flows merged (in veins) and bifurcated (in arteries) smoothly into the main blood vessel and branches, respectively, without any flow separation or secondary flow which accompanying large variation of shear stress. Vorticity was high in the inner regions for both types of vessels, where the radius of curvature varied greatly. The instantaneous flows in the arterial blood vessels showed noticeable pulsatility due to the heart beat, and the main features of the velocity waveforms, including pulsatile shape, retrograde flow, mean velocity, maximum velocity and pulsatile frequency, were significantly dependent on the pulsatile condition which dominates the arterial blood flow. In near future, these in vivo experimental results of blood flow measured in various extraembryonic blood vessels would be very useful to understand the hemodynamic characteristics of human blood flows and various blood flow researches for clinically useful hemodynamic discoveries as well.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• v.18 no.1
• /
• pp.15-29
• /
• 2024

A fetoscope is an optical endoscope, which is often applied in fetoscopic laser photocoagulation to treat twin-to-twin transfusion syndrome. In an operation, the clinician needs to observe the abnormal placental vessels through the endoscope, so as to guide the operation. However, low-quality imaging and narrow field of view of the fetoscope increase the difficulty of the operation. Introducing an accurate placental vessel segmentation of fetoscopic images can assist the fetoscopic laser photocoagulation and help identify the abnormal vessels. This study proposes a method to solve the above problems. A novel encoder-decoder network with a dual-path structure is proposed to segment the placental vessels in fetoscopic images. In particular, we introduce a channel attention mechanism and a continuous convolution structure to obtain multi-scale features with their weights. Moreover, a switching connection is inserted between the corresponding blocks of the two paths to strengthen their relationship. According to the results of a set of blood vessel segmentation experiments conducted on a public fetoscopic image dataset, our method has achieved higher scores than the current mainstream segmentation methods, raising the dice similarity coefficient, intersection over union, and pixel accuracy by 5.80%, 8.39% and 0.62%, respectively.

• Tuberculosis and Respiratory Diseases
• /
• v.53 no.2
• /
• pp.216-220
• /
• 2002

A 43 years old woman with a previous history of healed tuberculosis presented with a recurrent hemoptysis. On a bronchoscopy inspection, three nodular shaped mass-like lesions (0.5cm in diameter) were found on the right lower lobar bronchus. Massive hemoptysis occurred when the specimen were taken during bronchoscopy. The bleeding could not be controlled by non-surgical treatment. Consequently, she underwent a right lower lobectomy in order to control the bleeding. The patient died of respiratory failure 3 days later. A bronchoscopic biopsy revealed an abnormal blood vessel just beneath the bronchial respiratory epithelium.

• Journal of the Korean Society of Visualization
• /
• v.17 no.2
• /
• pp.10-16
• /
• 2019

Considering the role of viscosity in the hemorheology, the characteristics of non-Newtonian fluid are important in the pulsatile blood flows. Stenosis, with an abnormal narrowing of the vessel, contributes to block blood flows to downstream tissue and lead to plaque rupture. Therefore, systematic analysis of blood flow around stenosed vessels is crucial. In this study, non-Newtonian behaviors of blood analog fluids around the micro-stenosis with 60 % severity in diameter of $500{\mu}m$ was examined by using CFX under the pulsatile flow conditions with the period of 10 s. Viscosity information of two non-Newtonian fluids were obtained by fitting the value of normal blood and highly viscous blood. As the Newtonian fluid, the water at room temperature was used. During the pulsatile phase, wall shear stress (WSS) is highly oscillated. In addition, high viscous solution gives rise to increases the variation in the WSS around the micro-stenosis. Highly oscillating WSS enhance increasing tendency of plaque instability or rupture and damage of the tissue layer. These results, related to the influence on the damage to the endothelium or stenotic lesion, may help clinicians understand relevant mechanisms.

• Journal of the korean academy of Pediatric Dentistry
• /
• v.36 no.1
• /
• pp.145-149
• /
• 2009

Sturge-Weber Syndrome is a rare congenital disorder and is characterized by port wine nevus following one or more divisions of trigeminal nerve, ocular involvement(eg, glaucoma) and neurologic involvement(eg, epilepsy, mental retardation). Oral menifestations include unilateral blood vessel expansion of the oral mucosa and gingiva, gingival hyperplasia, giant tooth, ipsilateral large tongue, blood vessel anomaly of maxilla or mandible and abnormal eruption sequence. This case report is about 8-year-old Sturge-Weber Syndrome patient presented violet discoloration on upper gingiva and buccal mucosa, gingival hyperplasia and abnormal eruption sequence. In this case, we performed lingual frenectomy and periodic oral hygiene management, and obtained satisfactory result.

• Journal of Food Hygiene and Safety
• /
• v.28 no.3
• /
• pp.195-201
• /
• 2013

In atherosclerosis, blood vessels become sensitive to vessel-constricting agents leading to reduced control in the event of abrupt blood pressure changes. Mulberry trees (Morus alba L., MA) have been claimed to contain various bioactive principles that could possibly prevent atherosclerosis development caused by high cholesterol consumption. In order to examine whether MA feeding can prevent the sensitization of blood vessels, MA leaves were fed to rats for 8 weeks and pressor responses to vasoconstricting agents were assessed. Animals were pithed before blood pressure assessments to eliminate reflex compensation in vessel responses. Feeding diets containing high levels of cholesterol led to potentiated pressor responses to sympathetic nerve stimulation, or to injection of norepinephrine, phenylephrine, angiotensin II and vasopressin in pithed rats. These potentiated pressor responses were prevented in rats fed MA leaf-containing diets at 2 or 10% levels. It was also examined in anesthetized non-pithed rats whether similar cholestrol-related sensitization and MA prevention could be observed. However, high cholesterol-induced sensitization in pressor responses were not observed, suggesting that destruction of central cardiovascular control by pithing must have revealed the sensitization responses. It was concluded that MA leaves seem to be active in preventing abnormal blood vessel reactivity caused by hypercholesterolemia.

• 한국가시화정보학회:학술대회논문집
• /
• 2006.12a
• /
• pp.121-124
• /
• 2006

The arteries are very important in cardiovascular system and easily adapt to varying flow and pressure conditions by enlarging or shrinking to meet the given hemodynamic demands. The blood flow in arteries is dominated by unsteady flow phenomena due to heart beating. In certain circumstances, however, unusual hemodynamic conditions cause an abnormal biological response and often induce circulatory diseases such as atherosclerosis, thrombosis and inflammation. Therefore quantitative analysis of the unsteady pulsatile flow characteristics in the arterial blood vessels plays important roles in diagnosing these circulatory diseases. In order to verify the hemodynamic characteristics, in-vivo measurements of blood flow inside the extraembryonic arterial bifurcation cascade of chicken embryo were carried out using a micro-PIV technique. To analyze the unsteady pulsatile flow temporally, the (low images of RBCs were obtained using a high-speed CMOS camera at 250fps with a spatial resolution of $30{\mu}m\times30{\mu}m$ in the whole blood vessels. In this study, the unusual flow conditions such as flow separation or secondary flow were not observed in the arterial bifurcations. However, the vorticity has large values in the inner side of curvature of vessels. In addition, the mean velocity in the arterial blood vessel was decreased and pulsating frequency obtained by FFT analysis of velocity data extracted in front of the each bifurcation was also decreased as the bifurcation cascaded.

• Biomedical Science Letters
• /
• v.23 no.3
• /
• pp.201-207
• /
• 2017

Measuring the pulse wave velocity (PWV) is a non-invasive method for evaluating the stiffness of the vessel wall. While previous studies investigated the association of uric acid level with arterial stiffness, most did not consider smoking status and obesity as covariates. The objective of this study was to investigate the relationship between uric acid levels and arterial stiffness, considering smoking status and obesity. We studied 3390 subjects (1940 males and 1450 females). Abnormal PWV was also defined as the highest quartile of values in the subjects. Data were analyzed using Pearson correlation, t-test, and multiple regression analysis. Approximately 41.9% of men and 3.7% of women were current smokers. Prevalence of hypertension was 11.4% in men and 7.0% in women. In women, hyperuricemia was associated with abnormal PWV (OR 1.58; 95% CI 1.03~2.43). Hyperuricemia was also associated with abnormal PWV (OR 2.37; 95% CI 1.01~5.59) in non- or light male smokers with normal blood pressure. This study suggests that uric acid is associated with arterial stiffness in women and non-smoking men.

• Progress in Medical Physics
• /
• v.9 no.1
• /
• pp.23-28
• /
• 1998

We measured the flow at peripheral blood vessel of finger dorsum surface using noninvasive LDF(Laser Doppler Flowmeter). We investigated the flow properties between the normal and the diabetic with the Amplitude Spectral Densities of FFT analysis. We classified the diabetic as four groups of negative neuropathy, positive neuropathy, hyperthyroid and hypothyroid. And tested the neuropathic and thyroid effects of peripheral blood flow. As the results, the diabetic, the positive neuropathic and the hypothyroid respectively showed the abnormal blood flow properties on the contrary of the normal flow of negative neuropathic and hyperthyroid.

• Journal of the Korean Society of Radiology
• /
• v.81 no.3
• /
• pp.488-500
• /
• 2020

Accumulating evidence suggests that Alzheimer's disease (AD) is not only caused by accumulation of abnormal proteins, including amyloid and tau, but is also closely associated with abnormalities in the microvascular environment including the blood-brain barrier (BBB), both of which lead to neuroinflammation and neurodegeneration. Application of in vivo magnetic resonance imaging (MRI) has recently increased to assess BBB permeability in AD and related diseases. Here, we provide a narrative review of BBB permeability-related pathology in Alzheimer dementia and recent MRI research on BBB permeability changes in AD and related diseases. Furthermore, we briefly introduce the measurement of BBB permeability using MRI and its methodological issues.