Abstract:
:We used the finite element (FE) method to estimate the spatial sensitivity of a needle electrode for bioimpedance measurements. This current conducting needle with an insulated shaft was inserted in a saline solution and the current was measured at the neutral electrode. Model resistance and reactance were calculated and successfully compared with measurements on a laboratory model. The sensitivity field was described graphically based on these FE simulations.
journal_name
Physiol Measjournal_title
Physiological measurementauthors
Høyum P,Kalvøy H,Martinsen ØG,Grimnes Sdoi
10.1088/0967-3334/31/10/006subject
Has Abstractpub_date
2010-10-01 00:00:00pages
1369-79issue
10eissn
0967-3334issn
1361-6579pii
S0967-3334(10)49491-5journal_volume
31pub_type
杂志文章abstract::The effects of mechanical stimulation on hemodynamics, such as due to mechanotransduction in vascular endothelial cells, have been widely discussed recently. We previously proposed a resonance model in which the arterial system is treated as a pressure-transmitting system, and suggested that the application of externa...
journal_title:Physiological measurement
pub_type: 杂志文章
doi:10.1088/0967-3334/27/2/004
更新日期:2006-02-01 00:00:00
abstract::Epidemiological studies have associated the negative effects of sedentary time and sedentary patterns on health indices. However, these studies have used methodologies that do not directly measure the sedentary state. Recent technological developments in the area of motion sensors have incorporated inclinometers, whic...
journal_title:Physiological measurement
pub_type: 杂志文章
doi:10.1088/0967-3334/33/11/1887
更新日期:2012-11-01 00:00:00
abstract::The electrocardiogram is a representative signal containing information about the condition of the heart. The shape and size of the P-QRS-T wave, the time intervals between its various peaks, etc may contain useful information about the nature of disease affecting the heart. However, the human observer cannot directly...
journal_title:Physiological measurement
pub_type: 杂志文章
doi:10.1088/0967-3334/25/5/005
更新日期:2004-10-01 00:00:00
abstract::Focused impedance measurements (FIM) are used in several fields, and address the problem of measuring the volume impedance of an object within a volume conductor. Several electrode configurations are possible, and these have different properties. Sensitivity fields of four configurations have been investigated. We pre...
journal_title:Physiological measurement
pub_type: 杂志文章
doi:10.1088/0967-3334/35/6/1067
更新日期:2014-06-01 00:00:00
abstract::In this work, we describe a beat-by-beat method for assessing the clinical utility of pulsatile waveforms, primarily recorded from cardiovascular blood volume or pressure changes, concentrating on the photoplethysmogram (PPG). Physiological blood flow is nonstationary, with pulses changing in height, width and morphol...
journal_title:Physiological measurement
pub_type: 杂志文章
doi:10.1088/0967-3334/33/9/1491
更新日期:2012-09-01 00:00:00
abstract::Vascular and clinical assessments of arterio-venous fistula (AVF) function and access are important in patients undergoing or preparing to undergo renal dialysis. Objective assessment techniques include colour duplex ultrasound and more recently medical infrared thermography. Ideally, these should help assess problems...
journal_title:Physiological measurement
pub_type: 杂志文章
doi:10.1088/0967-3334/27/1/005
更新日期:2006-01-01 00:00:00
abstract::The main components responsible for the mechanical behavior of the arterial wall are collagen, elastin, and smooth muscle cells (SMCs) in the medial layer. We determined the structural and mechanical changes in porcine carotid arteries after administration of Triton® X-100, elastase, and collagenase using the inflatio...
journal_title:Physiological measurement
pub_type: 杂志文章
doi:10.1088/0967-3334/33/8/1335
更新日期:2012-08-01 00:00:00
abstract::In this study, a framework for the characterization of the dynamic interactions between RR variability (RRV) and systolic arterial pressure variability (SAPV) is proposed. The methodology accounts for the intrinsic non-stationarity of the cardiovascular system and includes the assessment of both the strength and the p...
journal_title:Physiological measurement
pub_type: 杂志文章
doi:10.1088/0967-3334/33/3/315
更新日期:2012-03-01 00:00:00
abstract:OBJECTIVE:In this paper, a support vector machine (SVM) approach using statistical features, P wave absence, spectrum features, and length-adaptive entropy are presented to classify ECG rhythms as four types: normal rhythm, atrial fibrillation (AF), other rhythm, and too noisy to classify. APPROACH:The proposed algori...
journal_title:Physiological measurement
pub_type: 杂志文章
doi:10.1088/1361-6579/aac7aa
更新日期:2018-06-25 00:00:00
abstract::The outflow conductance (C(out)) of the cerebrospinal fluid (CSF) system is a parameter considered to be predictive in selection for hydrocephalus surgery. C(out) can be determined through an infusion test. A new apparatus for performing infusion tests in a standardized and automated way was developed. The objective w...
journal_title:Physiological measurement
pub_type: 杂志文章
doi:10.1088/0967-3334/26/6/022
更新日期:2005-12-01 00:00:00
abstract::High-frequency (HF) oscillations in RR interval from 0.15-0.40 Hz are widely accepted as a measure of cardiac vagal outflow but the HF/RR relationship appears complex, particularly with longer RR intervals. The aim of this study was to evaluate the HF/RR interval relationship during free and paced breathing. HF power ...
journal_title:Physiological measurement
pub_type: 杂志文章
doi:10.1088/0967-3334/29/7/008
更新日期:2008-07-01 00:00:00
abstract::The specific heat capacity of tissue is a critical parameter for thermal therapies that act over a long period of time. It is also critical for thermoacoustic signal generation. We present ex vivo measurements of specific heat capacity performed by a dual-pin probe with tight temperature control of the specimen. One 3...
journal_title:Physiological measurement
pub_type: 杂志文章
doi:10.1088/0967-3334/32/11/N02
更新日期:2011-11-01 00:00:00
abstract::The pre-ejection period (PEP) has recently been described as a potential parameter for monitoring cardiac preload. This study further investigated the influence of changes in intravascular volume status and the application of positive end-expiratory pressure (PEEP) on the pre-ejection period. In ten pigs, ECG, arteria...
journal_title:Physiological measurement
pub_type: 杂志文章
doi:10.1088/0967-3334/26/6/012
更新日期:2005-12-01 00:00:00
abstract::Previous studies demonstrate that it is possible to evaluate a heart graft rejection condition using a bioimpedance technique by means of an intracavitary catheter. We propose to use a less invasive technique consisting in the use of a transoesophageal catheter and two standard ECG electrodes on the thorax. The aim of...
journal_title:Physiological measurement
pub_type: 杂志文章
doi:10.1088/0967-3334/32/7/S10
更新日期:2011-07-01 00:00:00
abstract:OBJECTIVE:To compare a novel cardiovascular magnetic resonance technique for the assessment of left ventricular (LV) mechanical discoordination by characterizing the endocardial center motion (ECM) in short-axis cine MRI in healthy volunteers and heart failure patients with left bundle branch block (HF-LBBB). APPROACH...
journal_title:Physiological measurement
pub_type: 杂志文章
doi:10.1088/1361-6579/aaaaa0
更新日期:2018-02-28 00:00:00
abstract::The point spread function (PSF) is the most widely used tool for quantifying the spatial resolution of imaging systems. However, prerequisites for the proper use of this tool are linearity and space invariance. Because EIT is non-linear it is only possible to compare different reconstruction algorithms using a standar...
journal_title:Physiological measurement
pub_type: 杂志文章
doi:10.1088/0967-3334/16/3a/021
更新日期:1995-08-01 00:00:00
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journal_title:Physiological measurement
pub_type: 杂志文章
doi:10.1088/0967-3334/24/2/357
更新日期:2003-05-01 00:00:00
abstract:OBJECTIVE:In this study, electroencephalography activity recorded during monotonous driving was investigated to examine the predictive capability of monopolar EEG analysis for fatigue/sleepiness in a cohort of train drivers. APPROACH:Sixty-three train drivers participated in the study, where 32- lead monopolar EEG dat...
journal_title:Physiological measurement
pub_type: 杂志文章
doi:10.1088/1361-6579/aae42e
更新日期:2018-10-30 00:00:00
abstract::The Timed Up and Go (TUG) test is a widely used measure of mobility and fall risk among older adults that is typically scored using a stopwatch. We tested the hypothesis that a body-fixed accelerometer can enhance the ability of the TUG to identify community-living older adults with a relatively high fall risk of unkn...
journal_title:Physiological measurement
pub_type: 杂志文章
doi:10.1088/0967-3334/32/12/009
更新日期:2011-12-01 00:00:00
abstract:OBJECTIVE:This paper aims to report on the accuracy of estimating sleep stages using a wrist-worn device that measures movement using a 3D accelerometer and an optical pulse photoplethysmograph (PPG). APPROACH:Overnight recordings were obtained from 60 adult participants wearing these devices on their left and right w...
journal_title:Physiological measurement
pub_type: 杂志文章
doi:10.1088/1361-6579/aa9047
更新日期:2017-10-31 00:00:00
abstract:OBJECTIVE:Predictive analytics monitoring that informs clinicians of the risk for failed extubation would help minimize both the duration of mechanical ventilation and the risk of emergency re-intubation in ICU patients. We hypothesized that dynamic monitoring of cardiorespiratory data, vital signs, and lab test result...
journal_title:Physiological measurement
pub_type: 杂志文章
doi:10.1088/1361-6579/aace95
更新日期:2018-07-16 00:00:00
abstract::Previous studies have used isokinetic dynamometry to assess joint torques and angles during passive extension of the knee, often without reporting upon methodological errors and reliability outcomes. In addition, the reliability of the techniques used to measure passive knee extension torque-angle and the extent to wh...
journal_title:Physiological measurement
pub_type: 杂志文章
doi:10.1088/0967-3334/34/11/1483
更新日期:2013-11-01 00:00:00
abstract::Monitoring the fetal behavior does not only have implications for acute care but also for identifying developmental disturbances that burden the entire later life. The concept, of 'fetal programming', also known as 'developmental origins of adult disease hypothesis', e.g. applies for cardiovascular, metabolic, hyperki...
journal_title:Physiological measurement
pub_type: 杂志文章,评审
doi:10.1088/1361-6579/aa5fca
更新日期:2017-05-01 00:00:00
abstract::Electrical impedance tomography (EIT) could be used as a portable non-invasive means to image the development of ischaemic stroke or haemorrhage. The purpose of this study was to examine if this was possible using time difference imaging, in the anesthetised rat using 40 spring-loaded scalp electrodes with applied con...
journal_title:Physiological measurement
pub_type: 杂志文章
doi:10.1088/0967-3334/37/6/765
更新日期:2016-06-01 00:00:00
abstract::The relation between the right-side (RS) electrical impedance phase angle (PA) and segmental PA in five configurations at 50 kHz was analyzed in 23 peritoneal dialysis male patients before complete drainage of the abdominal cavity. The impedance vector (Z/H) components were standardized by the height H of the subjects...
journal_title:Physiological measurement
pub_type: 杂志文章
doi:10.1088/0967-3334/29/9/N01
更新日期:2008-09-01 00:00:00
abstract::A magnetic pulse generator has been set up in order to study gastric activity. Two coils 1.05 m in diameter, arranged in a Helmholtz configuration, were used. The system generated magnetic field pulses higher than 15 mT, of duration 17.3+/-1.2 ms. Measurements were performed in 11 male volunteers, with average age 29....
journal_title:Physiological measurement
pub_type: 临床试验,杂志文章
doi:10.1088/0967-3334/25/5/015
更新日期:2004-10-01 00:00:00
abstract::ECG-gated electrical impedance tomographic spectroscopy (EITS) measurements of the lungs were taken on seven normal subjects in the frequency range 9.6 kHz to 614.4 kHz. The results show that in late systole the resistivity p' relative to the R-wave (i.e. p' = 1 at the R-wave) decreases consistently within the lung. I...
journal_title:Physiological measurement
pub_type: 杂志文章
doi:10.1088/0967-3334/17/4a/026
更新日期:1996-11-01 00:00:00
abstract:OBJECTIVE:Video and sound acquisition and processing technologies have seen great improvements in recent decades, with many applications in the biomedical area. The aim of this paper is to review the overall state of the art of advances within these topics in paediatrics and to evaluate their potential application for ...
journal_title:Physiological measurement
pub_type: 杂志文章,评审
doi:10.1088/1361-6579/ab0096
更新日期:2019-02-26 00:00:00
abstract::Obesity is associated with abnormal cardiac regulation by the autonomic nervous system (ANS), this being reversed by weight loss. Bariatric (weight-reduction) surgery can induce substantial long-term weight reductions. This study compares the acute influence on ANS control of two different types of bariatric surgery i...
journal_title:Physiological measurement
pub_type: 杂志文章
doi:10.1088/0967-3334/30/7/002
更新日期:2009-07-01 00:00:00
abstract::Electrocardiograms (ECGs) recorded from patients in intensive care were investigated to quantify any relationship between ECG signal quality and false monitoring alarms. False alarms are a considerable problem for nursing and medical staff as they distract from clinical care, and are also a problem for patients as the...
journal_title:Physiological measurement
pub_type: 杂志文章
doi:10.1088/0967-3334/37/8/1383
更新日期:2016-08-01 00:00:00