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The chemotherapy magnetically controlled under Magnetic Resonance Imaging (MRI) is currently one of the active areas of cancer research. This paper proposes a precise model of a therapeutic microrobot magnetically steered in blood vessels. This modeling approach takes into account the non-Newtonian behavior of blood, as well as wall effect on the blood's profile and robot-to-wall interaction forces...
Renal failure patients provide a good model of fluid overload with the process of hemodialysis leading to central hypovolemia. This study aims to assess if hemodialysis induces identifiable changes in ear photoplethysmographic waveform variability (PPGV). The results are based on data collected from 10 kidney failure patients undergoing regular hemodialysis; classified as either fluid removal or non-fluid...
Coronary angiography is limited in assessing the hemodynamic significance of a coronary lesion or the state of the coronary microcirculation. Noninvasive transthoracic (TTE) and transesophageal (TEE) Doppler echocardiography have been used to measure coronary blood flow velocity and coronary flow reserve and thus the physiology of the coronary vasculature (normal, stable or unstable lesions). A fundamental,...
Gastric impedance spectroscopy has been proposed as a method of monitoring mucosal injury due to hypoperfusion and ischemia in the critically ill. During validation tests for this procedure, it was found that 60% of the measurements had errors by factors inherent to the clinical setting, indicating that some kind of automatic error detection should be incorporated to potentially avoid the loss of...
Stanford type B aortic dissections (TB-AD), which split the descending aorta in a true and false lumen, have better in-hospital survival than type A dissections affecting the ascending aorta. However, short-term and long-term prognosis for the individual patient remains challenging, with one in four patients not surviving after 3 years. Towards a better understanding of the influence of tear location...
The aim of this preliminary study was to review the actual state of knowledge concerning the mechanisms underlying compression medical stockings action on the skin blood flow (SBF) in capillaries. SBF was assessed by measuring the thermal conductivity of living-tissues using μHematron ambulatory device. The investigation was performed for different postures using three standard French classes (10-15mmHg,...
Cardiovascular oscillations following spontaneous ventricular premature complexes (VPC) are characterized by a short-term heart rate fluctuation known as heart rate turbulence (HRT) described by the so-called turbulence onset (TO) and slope (TS). Despite a recent written consensus on the standard of HRT measurement, reproducibility data are lacking. Aim of the paper was a reproducibility study of...
In this paper we use the modified and integrated version of the balloon model in the analysis of fMRI data. We propose a new state space model realization for this balloon model and represent it with the standard A,B,C and D matrices widely used in system theory. A second order Padé approximation with equal numerator and denominator degree is used for the time delay approximation in the modeling...
The geometry of conduits derived from in vivo image data is subject to acquisition and reconstruction errors. This results in a degree of uncertainty in defining the bounding geometry for a patient-specific anatomical conduit. The impact of the conduit geometry uncertainty should be considered with respect to haemodynamic clinically relevant measures that may alter the perception and evaluation of...
The management and follow-up of chronic type B aortic dissections continues being a clinical challenge. Patients with chronic type B dissection have high mid/long term mortality mainly due to progressive aortic dilatation and subsequent rupture. To predict further dilatation, guidelines suggest follow-up of the total aortic diameter. However, dilatation is triggered by haemodynamic parameters (intra-luminal...
Arterial behavior analysis requires an accurate and dynamic knowledge of the stimuli and reactions involved. Belonging parameters quantification is performed by a data acquisition process and the application of existing models. However, it turns essentially to analyze the adjustment degree of the aforementioned models in terms of the arterial tree. Blood flow behavior as well as wall shear rate and...
This paper presents a system for touch-less heartbeat detection and a cardiopulmonary signal modeling approach. Using a vector network analyzer, a microwave system is tested for the detection of the heartbeat signal at a distance of 1 m from a person. The proposed system shows the ability of detecting the heartbeat signals with the possibility of tuning both frequency and power. Measurements are performed...
Numerous phantoms for human organs are commercially available or designed for scientific purposes. None of these combine the imaging possibility with color Doppler ultrasound (CDU) and computer tomography (CT) while providing vessel branches with bifurcations as natural landmarks. We designed, built and evaluated a flow model with vessel tree which can be imaged with CDU and CT. It aims at development...
The following topics are dealt with: medical signal processing; medical image processing; biomedical imaging; biosensors; chemical sensors; biomedical measurement; cardiology; haemodynamics; breathing; brain-computer interfaces; tissue engineering; medical robotics; and health care.
This study examines the effects of changing oxygen fractional inspiration ratio (FiO2), and nitrous oxide (N2O) for the improvement of cardiovascular control of mean arterial blood pressure (MAP) and heart rate (HR) in C57BL/6 mice under isoflurane anesthesia (1.5%) for up to 90 minutes post-induction. Heart rate variability (HRV) indices are also quantified under these conditions. The results indicate...
This paper proposes a new approach for the selection of a biophysical model describing the haemodynamic response function (HRF) measured in BOLD-fMRI data, based on model falsification techniques. Specifically, the novel method of Multiple Model Set-Valued Observers (MMSVOs) is introduced. The observers consider that the initial state lives in a set, the linear time-varying dynamic system obtained...
In this paper a new tool to assess viscoelastic and dielectric properties of human fluids is presented. Shear horizontal polarized surface acoustic waves (SH-SAW) are used to detect the viscoelastic properties of coagulating blood and blood plasma samples. One-port SAW resonators, with fundamental modes of 85, 170 und 340 MHz were developed. Additionally, their electrode structures can be used simultaneously...
Equilibrium radionuclide angiography images (ERNA) has been established as a useful modality for clinical evaluation of the ventricular function. Tomographic acquisition of ERNA (SPECT-ERNA) improves the quantification of ventricular function with planar ERNA, avoiding both the overlap of structures and the need of defining the best septal view which can be difficult in dilated ventricles. In this...
Successful management of cardiac heart failure requires a multifactorial approaching. It has been suggested that implantable hemodynamic long-term monitoring can improve patient care. This paper presents an analysis of the hemodynamic parameters commonly recorded, the most used implantable devices and their associated clinical trials. Newly implantable miniaturized sensors and devices are revisited...
The pressure-volume relationship of the heart was first reported more than a century ago. It was not widely accepted, however, until the mid-1970s. The pressure-volume diagram became a central theme of cardiac mechanics once it was shown to be a good representation of ventricular mechanics. Early in 1980s, the introduction of the ventricular interaction with afterload using effective arterial elastance...
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