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 measured. Measurements of hand bone mineral content (BMC) and BMD could be useful in assessing disease severity in early rheumatoid arthritis and in monitoring disease progression and response to therapeutic intervention. A phantom is required for evaluating the software, measuring long-term precision and comparing with other DXA methods. This note describes the design and evaluation of a hand phantom for use on a Lunar DPX-L dual-energy x-ray absorptiometer. The phantom consists of three sections representing the metacarpals, and proximal and distal phalanges, using aluminum and Perspex as the bone and lean tissue equivalents respectively. The BMD of the three sections is approximately 1.0, 0.6 and 0.3 g cm-2. The phantom demonstrates limitations in the potential accuracy of BMD determination at low densities using the Small Animal Software on the Lunar DPX-L. Improved recognition of low-density regions was obtained with the Lunar EXPERT with precision values of 0.9, 1.1 and 2.0% for the three sections of the phantom respectively.
journal_name
Physiol Measjournal_title
Physiological measurementauthors
Steel SA,Swann P,Langley G,Langton CMdoi
10.1088/0967-3334/18/3/008subject
Has Abstractpub_date
1997-08-01 00:00:00pages
233-40issue
3eissn
0967-3334issn
1361-6579journal_volume
18pub_type
杂志文章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::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::Although previous studies have established the feasibility of monitoring esophageal temperature during radiofrequency cardiac ablation using an esophageal temperature probe (ETP), some questions remain regarding its efficacy. The aims of this study were to study the effect of the location of the ETP on the temperature...
journal_title:Physiological measurement
pub_type: 杂志文章
doi:10.1088/0967-3334/28/5/001
更新日期:2007-05-01 00:00:00
abstract::We aim to investigate whether phase shift between respiratory oscillations in cerebral blood flow velocity (CBFV) and arterial blood pressure (ABP) is associated with changes in cerebral autoregulation (CA) or reflects the mechano-elastic properties of the cerebrovascular bed. The relationships between respiratory pha...
journal_title:Physiological measurement
pub_type: 杂志文章
doi:10.1088/1361-6579/38/2/310
更新日期:2017-02-01 00:00:00
abstract:OBJECTIVE:The performance of a novel unobtrusive system based on capacitively-coupled electrocardiography (ccECG) combined with different respiratory measurements is evaluated for the detection of sleep apnea. APPROACH:A sleep apnea detection algorithm is proposed, which can be applied to electrocardiography (ECG) and...
journal_title:Physiological measurement
pub_type: 杂志文章
doi:10.1088/1361-6579/abdf3d
更新日期:2021-01-22 00:00:00
abstract::The back-projected independent components (BICs) of single-trial, auditory P300 and contingent negative variation (CNV) evoked potentials (EPs) were derived using independent component analysis (ICA) and cluster analysis. The method was tested in simulation including a study of the electric dipole equivalents of the s...
journal_title:Physiological measurement
pub_type: 杂志文章
doi:10.1088/0967-3334/28/8/001
更新日期:2007-08-01 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 paper presents a method for adaptive decomposition of an electrical bio-impedance (BI) signal into two components: cardiac and respiratory. The decomposition of a BI signal is not a trivial process because of the non-stationarity of the signal components and overlapping of their harmonic spectra. An application sp...
journal_title:Physiological measurement
pub_type: 杂志文章
doi:10.1088/0967-3334/29/6/S02
更新日期:2008-06-01 00:00:00
abstract:OBJECTIVE:The aim of the study was to explore the feasibility of titrating tidal volume (V T) and positive end-expiratory pressure (PEEP) during one-lung ventilation (OLV) based on ventilation distribution and oxygenation. APPROACH:Twenty-four consecutive patients requiring intubation with a double-lumen tube and subs...
journal_title:Physiological measurement
pub_type: 杂志文章
doi:10.1088/1361-6579/aaaeb2
更新日期:2018-03-29 00:00:00
abstract::The aim of our study was to check the effect of varying blood volume in the chest and gravity on the distribution of ventilation and aeration in the lungs. The change in intrathoracic blood volume was elicited by application of lower body negative pressure (LBNP) of -50 cmH2O. The variation of gravity in terms of hypo...
journal_title:Physiological measurement
pub_type: 临床试验,杂志文章
doi:10.1088/0967-3334/26/2/003
更新日期:2005-04-01 00:00:00
abstract::The objective of this study was to adapt a novel near-infrared diffuse correlation spectroscopy (DCS) flow-oximeter for simultaneous and continuous monitoring of relative changes in cerebral blood flow (rCBF) and cerebral oxygenation (i.e. oxygenated/deoxygenated/total hemoglobin concentration: Δ[HbO2]/Δ[Hb]/ΔTHC) dur...
journal_title:Physiological measurement
pub_type: 杂志文章
doi:10.1088/0967-3334/35/10/2135
更新日期:2014-10-01 00:00:00
abstract::Several factors affect the viability of biosensor design. A computer-based model is being developed to enable the sources and effect of noise and variability within the sensor to be analysed. The work now presented details the modelling of the biochemical aspect of the biosensor model-the immunoassay. The equilibrium ...
journal_title:Physiological measurement
pub_type: 杂志文章
doi:10.1088/0967-3334/22/3/318
更新日期:2001-08-01 00:00:00
abstract::There are currently no objective means of quantifying chest wall vibrations during manual physiotherapy. The aims of the study were to (i) develop a method to quantify physiotherapy-applied forces and simultaneous changes in respiratory flow and pressure, (ii) assess the feasibility of using this method in ventilated ...
journal_title:Physiological measurement
pub_type: 杂志文章
doi:10.1088/0967-3334/28/9/004
更新日期:2007-09-01 00:00:00
abstract::The results of a preliminary clinical evaluation of a one-frequency electrical impedance tomography (EIT) system enabling static in vivo imaging are presented. The design of the measuring system and image reconstruction software are described. Thirty-one subjects were examined and divided into four clinical groups. Th...
journal_title:Physiological measurement
pub_type: 临床试验,杂志文章
doi:10.1088/0967-3334/23/1/304
更新日期:2002-02-01 00:00:00
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::In the present study, laser Doppler measurement was used to quantitatively investigate the microcirculatory effects of contact pressure stimulation (PS) underneath the Hoku acupoint and its nearby nonacupoint, to improve the understanding of the mechanisms underlying acupressure therapy. A control group (no PS applied...
journal_title:Physiological measurement
pub_type: 临床试验,杂志文章
doi:10.1088/0967-3334/31/6/007
更新日期:2010-06-01 00:00:00
abstract::Electrical impedance tomography (EIT) image reconstruction is an ill-posed problem requiring maximum measurement precision. Recent EIT systems claim 60 to 80 dB precision. Achieving higher values is hard in practice since measurements must be performed at relatively high frequency, on a living subject, while using com...
journal_title:Physiological measurement
pub_type: 杂志文章
doi:10.1088/0967-3334/27/5/S05
更新日期:2006-05-01 00:00:00
abstract::The effect of composition on the dielectric properties of hydrogels for biomedical applications is experimentally investigated. The hydrogels, containing hydroxyethylcellulose (HEC), are characterized by means of the impedance spectroscopy technique. The real and imaginary parts of the electrical impedance of the hydr...
journal_title:Physiological measurement
pub_type: 杂志文章
doi:10.1088/0967-3334/31/10/S02
更新日期:2010-10-01 00:00:00
abstract::The aim of this study was to establish whether analysis of the left ventricular pressure waveform provides indicative information about cardiac load and contractility and to develop an algorithm for computer-based assessment of changes in these variables. In eight healthy standard breed anaesthetized open-chest pigs, ...
journal_title:Physiological measurement
pub_type: 杂志文章
doi:10.1088/0967-3334/27/12/003
更新日期:2006-12-01 00:00:00
abstract::Electrical impedance tomography is an imaging method, with which volumetric images of conductivity are produced by injecting electrical current and measuring boundary voltages. It has the potential to become a portable non-invasive medical imaging technique. Until now, implementations have neglected anisotropy even th...
journal_title:Physiological measurement
pub_type: 杂志文章
doi:10.1088/0967-3334/28/7/S10
更新日期:2007-07-01 00:00:00
abstract::Near infrared spectroscopy (NIRS) is a widely employed method for assessment of regional cerebral oxygenation (RcStO2). RcStO2 values are expected to vary with changes in the relative amount of oxyhaemoglobin. The present experimental study aimed to assess the response of RcStO2 to controlled alterations of carotid bl...
journal_title:Physiological measurement
pub_type: 杂志文章
doi:10.1088/0967-3334/35/7/1439
更新日期:2014-07-01 00:00:00
abstract::A new method to image and quantify intra-abdominal haemorrhage using electrical impedance tomography (EIT) was tested in vivo. Supine peritoneal dialysis patients were monitored using an 8-electrode hemiarray placed on the anterior abdomen. EIT measurements were recorded using the EPack II data acquisition system befo...
journal_title:Physiological measurement
pub_type: 杂志文章
doi:10.1088/0967-3334/32/2/001
更新日期:2011-02-01 00:00:00
abstract::Electrical impedance is one of the most often used parameters for characterizing material properties, especially in biomedical applications. Electrical impedance spectroscopy (EIS), used for revealing both resistive and capacitive characteristics, is good for use in tissue characterization. In this study, a portable a...
journal_title:Physiological measurement
pub_type: 杂志文章
doi:10.1088/0967-3334/32/9/010
更新日期:2011-09-01 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: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 measurement of the complex respiratory impedance at a high temporal resolution is described. The measurement of impedance is correlated with the breathing cycle using electrical transthoracic impedance. This allows the determination of the complex impedance at any fixed point in the respiratory cycle, which result...
journal_title:Physiological measurement
pub_type: 杂志文章
doi:10.1088/0967-3334/14/3/019
更新日期:1993-08-01 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:OBJECTIVE:Atrial fibrillation (AF) causes marked risk for patients, while silent fibrillation may remain unnoticed if not suspected and screened. Development of comfortable yet accurate beat-to-beat heart rate (HR) monitoring with good AF detection sensitivity would facilitate screening and improve treatment. The purpo...
journal_title:Physiological measurement
pub_type: 杂志文章
doi:10.1088/1361-6579/aac9a9
更新日期:2018-06-27 00:00:00
abstract::EPR oximetry is a promising, relatively non-invasive method for monitoring the partial pressure of oxygen in tissue (PtO2) that has proved useful in following changes under various physiologic and pathophysiologic conditions. Optimal utilization of the method will be facilitated by systematic comparisons with other av...
journal_title:Physiological measurement
pub_type: 杂志文章
doi:10.1088/0967-3334/25/6/007
更新日期:2004-12-01 00:00:00
abstract::In magnetic resonance electrical impedance tomography (MREIT) we inject currents through electrodes placed on the surface of a subject and try to reconstruct cross-sectional resistivity (or conductivity) images using internal magnetic flux density as well as boundary voltage measurements. In this paper we present a st...
journal_title:Physiological measurement
pub_type: 杂志文章
doi:10.1088/0967-3334/24/2/367
更新日期:2003-05-01 00:00:00