Abstract:
:An analytic solution of the potential distribution on a 2D homogeneous disk for electrical impedance tomography under the complete electrode model is expressed via an infinite system of linear equations. For the shunt electrode model with two electrodes, our solution coincides with the previously derived solution expressed via elliptic integral (Pidcock et al 1995 Physiol. Meas. 16 77-90). The Dirichlet-to-Neumann map is derived for statistical estimation via nonlinear least squares. The solution is validated in phantom experiments and applied for breast contact impedance estimation in vivo. Statistical hypothesis testing is used to test whether the contact impedances are the same across electrodes or all equal zero. Our solution can be especially useful for a rapid real-time test for bad surface contact in clinical setting.
journal_name
Physiol Measjournal_title
Physiological measurementauthors
Demidenko Edoi
10.1088/0967-3334/32/9/008subject
Has Abstractpub_date
2011-09-01 00:00:00pages
1453-71issue
9eissn
0967-3334issn
1361-6579pii
S0967-3334(11)89659-0journal_volume
32pub_type
杂志文章abstract::Gated SPECT (GSPECT) was evaluated for the measurement of left ventricular ejection fraction (LVEF) by comparing with equilibrium gated radionuclide ventriculography (RNVG). A total of 99 subjects underwent GSPECT and RNVG imaging. All studies were acquired in list mode with GSPECT studies processed to give 16- and 8-...
journal_title:Physiological measurement
pub_type: 临床试验,杂志文章
doi:10.1088/0967-3334/22/2/312
更新日期:2001-05-01 00:00:00
abstract:OBJECTIVE:Electrical impedance tomography (EIT) is a functional imaging technique in which cross-sectional images of structures are reconstructed based on boundary trans-impedance measurements. Continuous functional thorax monitoring using EIT has been extensively researched. Increasing the number of electrodes, number...
journal_title:Physiological measurement
pub_type: 杂志文章
doi:10.1088/1361-6579/ab0daa
更新日期:2019-04-03 00:00:00
abstract:OBJECTIVE:Accurate bladder size estimation is an important clinical parameter that assists physicians, enabling them to provide better treatment for patients who are suffering from urinary incontinence. Electrical impedance tomography (EIT) is a non-invasive medical imaging method that estimates organ boundaries assumi...
journal_title:Physiological measurement
pub_type: 杂志文章
doi:10.1088/1361-6579/abaa56
更新日期:2020-12-18 00:00:00
abstract::Neural gastric electrical stimulation (NGES) is a new method for invoking gastric contractions under microprocessor control. However, optimization of this technique using feedback mechanisms to minimize power consumption and maximize effectiveness has been lacking. The present pilot study proposes a prototype feedback...
journal_title:Physiological measurement
pub_type: 杂志文章
doi:10.1088/0967-3334/30/3/006
更新日期:2009-03-01 00:00:00
abstract:OBJECTIVE:Cognitive reserve (CR) refers to the capacity of the brain to actively cope with damage via the implementation of remedial cognitive processes. Traditional CR measurements focus on static proxies, which may not be able to appropriately estimate dynamic changes in CR. This study therefore investigated the cogn...
journal_title:Physiological measurement
pub_type: 杂志文章
doi:10.1088/1361-6579/ab979e
更新日期:2020-07-07 00:00:00
abstract::Part I of this series showed that the five-element circuit model accurately mimics impedances measured using multi-frequency electrical impedance myography (MFEIM), focusing on changes brought on by disease. This paper addresses two requirements which must be met if the method is to qualify for clinical use. First, th...
journal_title:Physiological measurement
pub_type: 杂志文章
doi:10.1088/0967-3334/34/2/223
更新日期:2013-02-01 00:00:00
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::Electrical impedance tomography (EIT) measures the conductivity distribution within an object based on the current applied and voltage measured at surface electrodes. Thus, EIT images are sensitive to electrode properties (i.e. contact impedance, electrode area and boundary shape under the electrode). While some of th...
journal_title:Physiological measurement
pub_type: 杂志文章
doi:10.1088/0967-3334/32/7/S02
更新日期:2011-07-01 00:00:00
abstract::Dual-energy x-ray absorptiometry (DXA) is a precise, widely used method for measuring bone mineral density (BMD), usually of the lumbar spine and femoral neck. Recent developments, such as a lower x-ray tube current and pixel by pixel analysis, enable smaller bones and thinner tissues volumes, as in the hand, to be me...
journal_title:Physiological measurement
pub_type: 杂志文章
doi:10.1088/0967-3334/18/3/008
更新日期:1997-08-01 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::The left atrium (LA) plays an important role in the maintenance of hemodynamic and electrical stability of the heart. One of the conditions altering the atrial mechanical function is atrial fibrillation (AF), leading to an increased thromboembolic risk due to impaired mechanical function. Preserving the regions of the...
journal_title:Physiological measurement
pub_type: 杂志文章
doi:10.1088/0967-3334/35/5/763
更新日期:2014-05-01 00:00:00
abstract::Balance is the ability to maintain equilibrium while sitting or standing. There are a number of different methods which are used to assess balance: technical methods such as sway magnetometry, ataxia meter and force platforms, and clinical methods such as the functional reach test, Berg balance test and fall risk inde...
journal_title:Physiological measurement
pub_type: 杂志文章
doi:10.1088/0967-3334/21/4/309
更新日期:2000-11-01 00:00:00
abstract::The assessment and diagnosis of lower limb peripheral arterial occlusive disease (PAOD) is important since it can lead progressively to disabling claudication, ischaemic rest pain and gangrene. Historically, the first assessment has been palpation of the peripheral pulse since it can become damped, delayed and diminis...
journal_title:Physiological measurement
pub_type: 杂志文章
doi:10.1088/0967-3334/26/5/018
更新日期:2005-10-01 00:00:00
abstract::Generalizability theory was used to investigate the score consistency of observed extracellular fluid/intracellular fluid (ECF/ICF) ratio measurements for both the global and leg-segmental bio-impedance spectroscopy methods. The test instrument used was a Xitron Hydra ECF/ICF Bio-Impedance Analyzer System, model 4200 ...
journal_title:Physiological measurement
pub_type: 杂志文章,随机对照试验
doi:10.1088/0967-3334/27/4/005
更新日期:2006-04-01 00:00:00
abstract::Fetal heart rate monitoring is used for pregnancy surveillance in obstetric units all over the world but in spite of recent advances in analysis methods, there are still inherent technical limitations that bound its contribution to the improvement of perinatal indicators. In this work, a previously published wavelet t...
journal_title:Physiological measurement
pub_type: 杂志文章
doi:10.1088/0967-3334/35/8/1723
更新日期:2014-08-01 00:00:00
abstract::A photoacoustic technique is used for studying topically applied substance absorption in human skin. The proposed method utilizes a double-chamber PA cell. The absorption determination was obtained through the measurement of the thermal effusivity of the binary system substance-skin. The theoretical model assumes that...
journal_title:Physiological measurement
pub_type: 杂志文章
doi:10.1088/0967-3334/23/3/304
更新日期:2002-08-01 00:00:00
abstract::Electrical impedance tomography (EIT) is expected to become a valuable tool for monitoring mechanically ventilated patients due to its ability to continuously assess regional lung ventilation and aeration. Several sources of interference with EIT examinations exist in intensive care units (ICU). Our objectives are to ...
journal_title:Physiological measurement
pub_type: 杂志文章
doi:10.1088/0967-3334/32/12/F01
更新日期:2011-12-01 00:00:00
abstract:OBJECTIVE:Transfer function analysis (TFA) of dynamic cerebral autoregulation (dCA) requires smoothing of spectral estimates using segmentation of the data (SD). Systematic studies are required to elucidate the potential influence of SD on dCA parameters. APPROACH:Healthy subjects (HS, n = 237) and acute ischaemic str...
journal_title:Physiological measurement
pub_type: 杂志文章
doi:10.1088/1361-6579/ab7ddf
更新日期:2020-04-17 00:00:00
abstract::A new method for the measurement of pulmonary gas exchange during inhalational anaesthesia is described which measures fresh gas and exhaust gas flows using carbon dioxide as an extractable marker gas. The theoretical precision of the method was compared by Monte Carlo modelling with other approaches which use marker ...
journal_title:Physiological measurement
pub_type: 杂志文章
doi:10.1088/0967-3334/25/1/001
更新日期:2004-02-01 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::A method was developed for simultaneously measuring plasma resistance, cell interior resistance and cell membrane capacitance of blood. A three-element circuit model for simulating the impedance of blood was evaluated by comparing measured and calculated impedance frequency curves and was found feasible. The values of...
journal_title:Physiological measurement
pub_type: 杂志文章
doi:10.1088/0967-3334/14/2/006
更新日期:1993-05-01 00:00:00
abstract::Temporal variability of parameters which describe dynamic cerebral autoregulation (CA), usually quantified by the short-term relationship between arterial blood pressure (BP) and cerebral blood flow velocity (CBFV), could result from continuous adjustments in physiological regulatory mechanisms or could be the result ...
journal_title:Physiological measurement
pub_type: 杂志文章
doi:10.1088/0967-3334/29/4/006
更新日期:2008-04-01 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:OBJECTIVE:To investigate the effect of maternal hyperoxygenation on fetal heart rate (FHR) when applied for suspected fetal distress during the second stage of term labor. APPROACH:A single-center randomized controlled trial was conducted in a tertiary care hospital in The Netherlands. Participants were included durin...
journal_title:Physiological measurement
pub_type: 杂志文章
doi:10.1088/1361-6579/abc0b6
更新日期:2020-12-11 00:00:00
abstract::The use of artificial neural networks (ANNs) to interpret sleep monitoring signals is described. Recordings from ten infants with apparent life threatening episodes were assigned into training feedforward R-PROP networks. In order to separate good signal from artefact, 60 second time frames of SaO2 and TcPO2 signals w...
journal_title:Physiological measurement
pub_type: 临床试验,杂志文章
doi:10.1088/0967-3334/21/3/401
更新日期:2000-08-01 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::Despite significant advances in adult clinical electrocardiography (ECG) signal processing techniques and the power of digital processors, the analysis of non-invasive foetal ECG (NI-FECG) is still in its infancy. The Physionet/Computing in Cardiology Challenge 2013 addresses some of these limitations by making a set ...
journal_title:Physiological measurement
pub_type: 杂志文章
doi:10.1088/0967-3334/35/8/1569
更新日期:2014-08-01 00:00:00
abstract::A simple wearable device for sit-to-stand timing detection was designed and constructed with rate gyroscopes and accelerometers and a dedicated adaptive algorithm. The method was validated by comparison with optoelectronic equipment. Results from the comparison showed a maximal error always lower than 2.5 x 10(-2) s f...
journal_title:Physiological measurement
pub_type: 杂志文章
doi:10.1088/0967-3334/27/8/006
更新日期:2006-08-01 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:OBJECTIVE:The Actiwatch 2 (AW2) is a wrist-worn accelerometer typically used to measure sleep. Although it can measure physical activity, there is limited evidence supporting its validity. We assessed the validity and reliability of the AW2 to measure sedentary behavior and physical activity (light, moderate, vigorous ...
journal_title:Physiological measurement
pub_type: 杂志文章
doi:10.1088/1361-6579/aba80f
更新日期:2020-09-04 00:00:00