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The early detection of biomechanical modifications in the arterial wall could be used as a predictor factor for various diseases, for example hypertension or atherosclerosis. In this work a transient elastography technique is used for the in vitro evaluation of the arterial wall elasticity. The obtained Young modulus is compared with the one obtained by a more classical approach: pressure-diameter...
Current work is a part of long term research, which aim is to study the possibilities to diagnose the atherosclerosis in early stadium by using pulse wave velocity and its waveform analysis. The mobile experimental measurement complex is built and technically tested for the long term study in hospital. Measurement complex consists of ten physiological signal recording channels and reference devices:...
Atrial tachycardias are the most common cardiac arrhythmias in clinical practice, which induce changes in atrial properties that help to perpetuate them. These changes are called “atrial remodeling”. Recent studies have shown that rapid ectopic activity principally on the pulmonary veins can trigger reentrant mechanisms and lead to atrial tachycardias. However, the influences of ectopic foci location,...
Small calibre (<;;6mm) polytetrafluoroethylene (PTFE) bypass grafts have poor medium and long term patency due to the development of neointimal hyperplasia at the distal anastomosis. The inelasticity of PTFE is implicated in this mechanism of failure. We have developed a novel polyhedral oligomeric silsesquioxane (POSS) nanocage incorporated into a poly(carbonate)urethane (PCU) biomaterial with...
In this study, a new portable type Self-Monitoring Blood Glucose (SMBG) device, which is driven automatically from the blood sampling to the blood glucose measurement, is developed to establish the point-of-care technology in the ubiquitous medical care. It aims to overcome human errors due to the complicated manual operation of commercial SMBG devices. In this study, I mainly discuss the development...
We have already reported our attempt to constrain direction of microcapsules in flow owing to an acoustic radiation force. However, the diameter of capsules was too large not to be applied in vivo. Furthermore, acoustic radiation force affected only in focal area because focused ultrasound was used. Thus we have improved our experiment by using microcapsules as small as blood cells and introducing...
Hepatic vessel structure is very important to ensure the blood supply of the liver tissue. Therefore the knowledge of the hepatic vessel system is indispensable in liver surgery planning, for example before performing a liver resection. The purpose of this paper is to present an easy to use and fast method concerning hepatic vessel segmentation and risk analysis, which is intended to be applicable...
The Pulse Transit Time (PTT) is generally assumed to be a good surrogate measure to comfortably track blood pressure (BP) and blood pressure changes. This paper investigates PTT variations for healthy young subjects during a sequence of short-term physical exercises. PTT was measured by two different methodologies having different measurement accuracies as well as underlying assumptions: the total...
This paper reports a method that aims to quantify the changes of tumour vascular structure as a result of drug treatment. The measures we have investigated to date include: vessel radii, inter-branch lengths, tortuosity and branch angles. We show that the distribution of vessel radii is better modelled as a gamma distribution as opposed to the log-normal distribution asserted by other researchers...
The Empirical Mode Decomposition (EMD) is a method to decompose non linear, non stationary time series into a sum of different modes, named Intrinsical Mode Functions each one having a characteristic frequency. In the present work we used the EMD to investigate the properties of the recorded sounds from the Arteriovenous fistula on hemodialysis patients. Phonoangiographic signals coming from two different...
Intracranial Pressure (ICP) measurements are of great importance for the diagnosis, monitoring and treatment of many vascular brain disturbances. The standard measurement of the ICP is performed invasively by the perforation of the cranial scalp in the presence of traumatic brain injury (TBI). Measuring the ICP in a noninvasive way is relevant for a great number of pathologies where the invasive measurement...
Acupuncture is used widely in oriental medicine. But it is difficult to stimulate continuously or intermittently in daily life with conventional acupuncture. An acupoint stimulation device using focused ultrasound has been developed. Because the device size is about 6 mm in diameter, it can be easily put on the skin during daily life. Appropriate stimulation intensity and pattern can be chosen by...
Cardiovascular diseases are the main causes of mortality, not only in Brazil, but around the world. The use of acupuncture as a complementary and alternative treatment for cardiovascular diseases has been suggested for animals as well as human beings. Possible advantages in using acupuncture are the low cost of treatment and low risks of collateral damage from a combination of acupuncture with other...
Wall artery viscoelastic properties (WAVP) are correlated with structural and functional state of the arterial system. An accurate estimation of these properties is achieved measuring wall instantaneous diameter and pressure signals. The aim of this work was to evaluate a new non invasive estimation method of the instantaneous arterial diameter (D), and consequently, WAVP. Ten common carotid arteries...
The paper proposes a novel Extensible Markup Language (XML) based format called ART-ML that aims at supporting the interoperability and the reuse of models of blood flow, mass transport and plaque formation, exported by ARTool. ARTool is a platform for the automatic processing of various image modalities of coronary and carotid arteries. The images and their content are fused to develop morphological...
We proposed a novel laser-driven short-term heating angioplasty to realize restenosis-suppressive angioplasty for peripheral artery disease. In this study, we investigated the chronic intimal hyperplasia formation after the short-term heating dilatation in vivo, as well as the thermal damage calculation on arterial smooth muscle cells (SMCs). The prototype short-term heating balloon catheter with...
Sickle cell anemia (SCA) is a genetic disease which is characterized by painful episodes of vascular occlusions. In the present study, we investigated a potential contribution of the autonomic nervous system (ANS) in initiating such episodes. We observed prominent decreases in microvascular perfusion in response to spontaneous sighs, which may increase the likelihood of red blood cell polymerization...
In this study we propose a method to continuously assess the changes of spontaneous baroreflex sensitivity (BRS). Systolic arterial pressure and RR intervals are analyzed by time-frequency analysis to estimate their instantaneous powers as well as the time-course of their spectral coherence. The BRS estimated in classical frequency bands is compared to the BRS estimated in dynamic frequency bands...
Low systemic vascular resistance (SVR) can be a useful indicator for early diagnosis of critical pathophysiological conditions such as sepsis, and the ability to identify low SVR from simple and noninvasive physiological signals is of immense clinical value. In this study, an SVR classification system is presented to recognize the occurrence of low SVR, among a heterogenous group of patients (N =...
Magnetic Resonance Targeting (MRT) uses MRI for gathering tracking data to determine the position of microscale entities with the goal of guiding them towards a specific target in the body accessible through the vascular network. At full capabilities, a MRT platform designed to treat a human would consist of a clinical MRI scanner running special algorithms and upgraded to provide propulsion gradient...
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