Technology and Health Care - Volume 4, issue 1

Authors: Pedotti, Antonio

Article Type: Editorial

DOI: 10.3233/THC-1996-4101

Citation: Technology and Health Care, vol. 4, no. 1, pp. 1-2, 1996

Authors: Beltrame, F. | Pernice, A. | Tagliasco, V.

Article Type: Review Article

DOI: 10.3233/THC-1996-4102

Citation: Technology and Health Care, vol. 4, no. 1, pp. 3-8, 1996

Authors: Rolfe, P.

Article Type: Review Article

DOI: 10.3233/THC-1996-4103

Citation: Technology and Health Care, vol. 4, no. 1, pp. 9-13, 1996

Authors: Heiss, W.-D.

Article Type: Review Article

DOI: 10.3233/THC-1996-4104

Citation: Technology and Health Care, vol. 4, no. 1, pp. 15-29, 1996

Authors: Pourcelot, L. | Lethiecq, M. | Patat, F. | Roncin, A. | Tranquart, F. | Berson, M.

Article Type: Review Article

DOI: 10.3233/THC-1996-4105

Citation: Technology and Health Care, vol. 4, no. 1, pp. 31-36, 1996

Authors: Donato, Luigi | Mambrito, Bruno

Article Type: Review Article

Abstract: In the artificial heart area, device evolution and evolution of application criteria have been synergetic in promoting advancement in the entire sector. In fact, limitations of conventional therapies prompted the short-term use of devices for supporting patients until heart transplantation or until recovery of natural heart function. This in tum stimulated device diversification. A first class of new intraventricular blood pumps, allowing simplified application procedures, but with limitation in blood flow, have been developed for short term mechanical support. Another class of devices, with more implantable components, have been developed for longer duration applications, and higher quality of patient life …during the implant period. These temporary but progressively longer duration clinical applications in patients waiting for heart transplantation, demonstrated the clinical feasibility of permanent support or substitution of a failing heart; an application intended as an alternative to heart transplantation that is greatly limited by donor’s organ availability. Research efforts are now focused on establishing readiness for permanent clinical use of totally implantable heart replacing systems, or of implantable devices for assisting left ventricular function. Show more

Keywords: Artificial heart, TAH, VAD, mechanical assistance

DOI: 10.3233/THC-1996-4106

Citation: Technology and Health Care, vol. 4, no. 1, pp. 37-41, 1996

Authors: Camevali, P. | Ferrigno, G. | Aliverti, A. | Pedotti, A.

Article Type: Research Article

Abstract: A method for kinematic analysis of chest wall motion is presented, based on a TV-image processor which allows a three-dimensional assessment of volume change of the trunk by automatically computing the co-ordinates of several passive markers placed on relevant landmarks of the thorax and abdomen. The parallel computation used for the image processing allows a real time recognition of the passive markers with the necessary accuracy. A geometric model also allows the on-line computation of the contribution to the chest volume by the different parts. For this purpose the model is based on 96 tetrahedrons which can be grouped into …16 compartments and into four sections representing: upper thorax (reflecting the action of neck and parasternal muscles and the effect of pleural pressure), lower thorax (reflecting the action of diaphragm and the effect of pleural and abdominal pressure), upper and lower abdomen (reflecting the actions of diaphragm and abdominal muscles). The volume can also be split into two vertical sections pointing out asymmetries between the right and left side. The method is non-invasive, non-ionizing and leaves the subject maximum freedom of movement during the test, thus being suitable for routine clinical analysis. The monitoring of the subject can be prolonged in time and can be performed in different postures: standing, sitting, supine and lying on one side. The method was tested on eight healthy subjects showing good accuracy, reliability and reproducibility. Show more

Keywords: Chest motion analysis, optical pletismography, 3D movement analysis

DOI: 10.3233/THC-1996-4107

Citation: Technology and Health Care, vol. 4, no. 1, pp. 43-65, 1996

Authors: Rabenstein, K. | McShane, A.J. | McKenna, M.J. | Dempsey, E. | Keaveny, T.V. | Freaney, R.

Article Type: Research Article

Abstract: Direct sensor implantation for continuous biochemical monitoring has proved disappointing, but microdialysis sampling devices can serve as a biocompatible patient-sensor interface. We propose a novel “MiniShunt” extracorporeal microdialysis sampling circuit designed to sample core blood, and report the performance of different microdialysis probe membrane types and sizes with pumped and non-pumped blood flow in anaesthetised dogs. Discrete microdialysate and plasma samples collected during glucose and lactate monitoring were analysed with a YSI analyzer and showed microdialysis efficiency (% relative recovery) in excess of 95% for both analytes using fibres of greater than 70 mm2 internal surface area. Pumped veno-venous …extracorporeal blood microdialysis sampling of this type could provide a suitable interface for future multi-analyte on-line biosensor applications in critically ill patients. Show more

Keywords: Microdialysis, extracorporeal circulation, monitoring, physiologic, blood glucose, lactates

DOI: 10.3233/THC-1996-4108

Citation: Technology and Health Care, vol. 4, no. 1, pp. 67-76, 1996

Authors: Bove, M. | Genta, G. | Verreschi, G. | Grattarola, M.

Article Type: Research Article

Abstract: The main purpose of this paper is to describe several software tools specifically adapted to characterize the electrophysiological behavior of a population of neurons coupled to a planar array of microtransducers by analyzing the recorded signals. Both graphic and signal processing tools are considered. They include: image analysis of the neuronal network topology, peak detection procedure, multi-graphics visualization, spike classification, cross-correlation, interspike and interbursting interval analysis. These tools are utilized to characterize changes induced in the electrophysiological behavior of populations of cultured neurons by modifications to the medium-culture.

Keywords: Cell culture, neuronal networks, electrophysiological signals, signal and image processing

DOI: 10.3233/THC-1996-4109

Citation: Technology and Health Care, vol. 4, no. 1, pp. 77-86, 1996

Authors: Sparacino, G. | Cobelli, C.

Article Type: Research Article

Abstract: Insulin secretion rate (ISR) in vivo is reconstructed by deconvolution from plasma concentration of C-peptide (CP), a peptide with linear kinetics which is co-secreted with insulin but is not extracted by the liver. Deconvolution requires the knowledge of the CP impulse response. A two-exponential (2E) model is usually chosen to describe the CP impulse response but a one-exponential (IE) model is also used in the literature. The purpose here is to discuss the domain of validity of the IE model in reconstructing the ISR by deconvolution. In particular, we show that the IE model can be reliably used only if …the ISR spectrum is concentrated in a narrow frequency band and a suitable input is designed for its identification. Show more

Keywords: Physiological system, system identification

DOI: 10.3233/THC-1996-4110

Citation: Technology and Health Care, vol. 4, no. 1, pp. 87-95, 1996

Authors: Botnar, R. | Scheidegger, M.B. | Boesiger, P.

Article Type: Research Article

Abstract: The quantitative assessment of velocity fields can help to get a better understanding of complicated flow patterns which are considered to play an important role in atherosclerotic plaque formation. Magnetic resonance imaging offers the possibility of non-invasive visualization and quantification of blood flow in many larger human arteries and veins. However, the assessment of complex blood flow patterns with conventional gradient echo flow sequences sutler from severe image artifacts. In order to overcome these problems, a partial echo signal acquisition technique which strongly reduces such artifacts may be applied. Using this technique, three dimensional velocity fields were measured in a …bifurcation model, in the human carotid bifurcation and in the human aorta, right downstream of the aortic valve. Show more

Keywords: Complex blood flow, magnetic resonance imaging, atherosclerosis

DOI: 10.3233/THC-1996-4111

Citation: Technology and Health Care, vol. 4, no. 1, pp. 97-112, 1996

Authors: Müller, R. | Koller, B. | Hildebrand, T. | Laib, A. | Gianolini, S. | Rüegsegger, P.

Article Type: Research Article

Abstract: Micro-computed tomography (μCT) is an emerging technique for the non-destructive assessment and analysis of the three-dimensional cancellous bone architecture. However, the procedures and applications used to quantify bone structures are not yet standardized. The aim of this study was to provide more insight in the resolution-dependency of microstructural properties of three-dimensional trabecular bone. Ten iliac crest bone biopsies were measured using a newly devised μCT system providing a nominal isotropic resolution of 14 μm. To study the resolution dependency, the measured data were reconstructed on reduced image arrays with reduction factors ranging from 2 to 20. To assess the structural …properties, morphometric parameters were computed based on a truly three-dimensional approach. The results showed a strong resolution dependency of the structural properties and that, if very precise results are needed, only the highest resolution will predict the correct values. Nevertheless, since the properties either decrease or increase monotonously up to a nominal resolution of about 175 μm, the values appear to be restorable using a suitable calibration procedure. Show more

Keywords: Micro-computed tomography (μCT), trabecular bone architecture, quantitative bone morphology, 3D structural analysis, image resolution

DOI: 10.3233/THC-1996-4112

Citation: Technology and Health Care, vol. 4, no. 1, pp. 113-119, 1996

Authors: Di Rienzo, M. | Castiglioni, P. | Parati, G. | Mancia, G. | Pedotti, A.

Article Type: Research Article

Abstract: This paper focuses on a number of methods for the analysis of the relationship between the arterial baroreflex and different components of blood pressure and heart rate variability. Broad-band spectral analysis techniques have allowed us to obtain experimental evidence that the arterial baroreflex exerts its influence not only on fast but also on slow components of blood pressure and heart rate, i.e., on components with periods longer than 60 sec. Focusing on faster changes in blood pressure and heart rate, both time domain and frequency domain techniques have been developed to track the sensitivity of baroreflex heart rate modulation over …time, either in laboratory or in daily life conditions. These approaches have considerably broadened our understanding of the role of baroreflex modulation of the heart and peripheral circulation in a number of pathological and physiological conditions. Show more

DOI: 10.3233/THC-1996-4113

Citation: Technology and Health Care, vol. 4, no. 1, pp. 121-128, 1996