Technology and Health Care - Volume 10, issue 1

Authors: Singh, Gurmak | O'Donoghue, John | Soon, Chia Kee

Article Type: Research Article

Abstract: Physicians, hospitals and medical schools have been exploring the uses of telemedicine since 1964, primarily in the area of medical education. While the explosion of interest in telemedicine over the past five or six years has seen an increase in the use of telecommunications technology. At present, telemedicine is utilised by health providers in a growing number of medical specialties including but not limited to: dermatology, oncology, radiology, surgery, cardiology, psychiatry and home health care. The emergence of telemedicine has altered the structure of this industry, the management of the health providers and is likely to have an impact on …the patients and society at large. Show more

DOI: 10.3233/THC-2002-10101

Citation: Technology and Health Care, vol. 10, no. 1, pp. 1-10, 2002

Authors: Shoucri, Rachad M.

Article Type: Research Article

Abstract: A mathematical approach is given by which the intramyocardial stress σ induced in the passive medium of the myocardium is expressed as the sum of the stress ( σ ) p induced in the passive medium by the left ventricular pressure P and the external pressure P o , and the stress ( σ ) d induced in the passive medium by the active force generated by the muscular fibers of the myocardium. Relations between σ = ( σ ) p …+ ( σ ) d , the left ventricular elastance E and the residual volume V d are also derived. Applications to experimental data are given and clinical implications of the results are discussed. Show more

Keywords: muscular fiber stress in the myocardium, end-systolic pressure-volume relation, stress-strain analysis in the myocardium, cardiac mechanics

DOI: 10.3233/THC-2002-10102

Citation: Technology and Health Care, vol. 10, no. 1, pp. 11-22, 2002

Authors: Amirouche, F. | Gonzalez, M. | Koldoff, J. | Tioco, J. | Ham, K.

Article Type: Research Article

Abstract: This paper addresses the mechanics of the finger/pulley system when subjected to various excisions and repairs. Several cadaver hands were used to study the finger/pulley's function, finger joint dynamics, and the relationship between tendon excursion and finger joint angles of rotation. By using a method of continuous and simultaneous data acquisition of the entire finger joint's motion, a more detailed analysis was achieved. Our experimental investigation is based on the use of four micro-potentiometers inserted at the finger's joints and a pulley system to simulate tendon excursion. Using this procedure, a detailed kinematic analysis of the entire finger was performed. …This included analysis of the intact hand, various pulley excisions, and reconstruction. In addition to introducing a new method of acquisition, a mathematical model was developed for the inverse dynamic analysis of the finger pulley system. From this model, the torques required at the joints for the motion were computed. The results provided new insight into possible ways of characterizing kinematic changes resulting from pulley damage and repair. Show more

Keywords: finger-pulley system, hand mechanics, excisions, pulley repair, Tendon excursion

DOI: 10.3233/THC-2002-10103

Citation: Technology and Health Care, vol. 10, no. 1, pp. 23-31, 2002

Authors: Steinau, G. | Krischer, S. | Staatz, G. | Marx, A. | Schumpelick, V.

Article Type: Research Article

Abstract: Extrahepatic bile duct disease is a rare finding in infancy and early childhood. However, there is an increasing number of patients operated at this age reported in the literature. This increase may have multifactorial reasons, e.g. real increase, better ability of detection as a result of better diagnostic techniques and knowledge of predisposing factors of extrahepatic bile duct disease in childhood, especially in early childhood and infancy. The following report describes three cases of extrahepatic bile duct disease in infancy and early childhood treated at the Department of Surgery of the University of Technology in Aachen, Germany. From 1986 …to 1998 28 Patients below 18 years were operated at our Department of Surgery. There was a recognizable increase of patients in 1996, 1997 and 1998. Whereas from 1986 to 1995 an average of 1.5 Cholecystectomies in pediatric patients were done, the years from 1996 to 1998 show an average of 5,33 patients operated per year. Every patient obtained a Cholecystectomy – 15 conventional open Cholecystectomies and 13 Laparoscopies, which were primarily performed in children in our clinic in 1991. Besides cholecystectomy in one case a Hepaticoenterostomy was necessary and in another case surgical treatment of the Papilla of Vater and the Common Bile Duct was performed. In 22 patients symptomatic Cholelithiasis was the indication for a Cholecystectomy. Another Patient had a gallbladder polyp consisting of heterotopic Duodenal glands, two patients showed a shock gallbladder following trauma and cardiac operation and three patients had chronic Cholecystitis without gallstones. Clinical data was collected and retrospectively reviewed. Additionally, we created a personal questionnaire to carry through a follow-up. Three Patients were less than 3 1/2 years old. The youngest patient was only 5 months old and presented with Cholelithiasis and Choledocholithiasis. Another male patient, aged 2 years received a Cholecystectomy and a Hepaticoenterostomy because of a Choledochal Cyst Type Ib (Todani-Classification). And a 3-year-old-girl had a shock gallbladder caused by thromboembolism following cardiac operation nine days before. Show more

Keywords: cholelithiasis, choledocholithiasis, choledochal cyst, infancy, early childhood, shock gallbladder

DOI: 10.3233/THC-2002-10104

Citation: Technology and Health Care, vol. 10, no. 1, pp. 33-37, 2002

Authors: Ovadia-Blechman, Zehava | Einav, Shmuel | Zaretsky, Uri | Castel, David | Toledo, Eran | Eldar, Michael

Article Type: Research Article

Abstract: This study describes a novel method for assessing stenotic severity, based on simultaneous pressure and flow wave measurements. Pressure and flow measurements were performed in latex and rubber tubes, and in a clinically-used vascular graft. Pressure waves were recorded at several degrees of stenosis and at different distances proximal to the stenosis. Pressure wave versus flow wave was plotted. Internal pressure-flow loop area (PFLA), loop slope and pressure-axis intercept were calculated. Values of these three indices significantly increased with increasing degrees of stenosis P < 0.001 ). Similar phenomenon was observed during in-vivo experiments. Polynomial functions were …fitted, resulting in an excellent PFLA variable/percent stenosis correlation, independent of distance between sensor and stenosis (R 2 > 0.96 ). In addition, tube compliance was measured and found to correlate with the polynomial coefficients (| R | > 0.9 ). This innovative approach could significantly contribute to detecting and evaluating arterial stenoses, and to characterize the elasticity of the artery. Show more

Keywords: hemodynamics, blood pressure, blood flow, arterial stenosis, elasticity

DOI: 10.3233/THC-2002-10105

Citation: Technology and Health Care, vol. 10, no. 1, pp. 39-56, 2002

Authors: Walsh, Edward G. | Anayiotos, Andreas | Doyle, Mark | Pohost, Gerald M.

Article Type: Research Article

Abstract: Myocardial perfusion imaging using Gd contrast agents is typically performed with bolus injections of the contrast agent using a power injector to provide for consistent and sufficiently rapid injection rates for all patients. For protocols in which a peripheral venous injection is called for (e.g. antecubital vein) injection catheters of 18 ga are used where vessel geometry permits. In some patients, particularly women with smaller veins, 20 and 22 ga catheters are used. The effect of catheter size and pressure tubing length can result in high injection pressures that occasionally cause leakage or connector failure. The viscosity of the contrast …agent also impacts injection pressure. In this study, a simulation of the injection pathway was constructed with time resolved pressures measured at two points in the pathway. Pressure drops were calculated for a typical MR perfusion injection protocol. Show more

Keywords: magnetic resonance, perfusion imaging, contrast agents

DOI: 10.3233/THC-2002-10106

Citation: Technology and Health Care, vol. 10, no. 1, pp. 57-63, 2002

Authors: Matthys, Koen | Verdonck, Pascal

Article Type: Research Article

Abstract: Arterial tonometry allows non-invasive and continuous registration of the arterial pressure waveform, by applanating (flattening) a superficial artery supported by bone with an external transducer. Inspired by ocular tonometry used for eye disease diagnosis, G.L. Pressman and P.M. Newgard built the first arterial tonometer in 1963, and derived a discrete, linear mechanical model. Accuracy remained poor until new sensor production techniques (silicon technology) arrived. G.M. Drzewiecki et al. published a second, more elaborate theoretical model for tonometer positioning in 1983. Few years later, the first modern tonometers were commercialised. Although the problems of sensor positioning, motion artefacts and calibration still …exist, the tonometer has proven its usefulness in arterial compliance and hypertension studies. Attention should now go to analysis of the arterial pressure waveforms, and the combination with other signals (e.g. flow wave morphology) to allow a complete non-invasive haemodynamical description of the heart and the arterial tree. Show more

Keywords: arterial, applanation, tonometry

DOI: 10.3233/THC-2002-10107

Citation: Technology and Health Care, vol. 10, no. 1, pp. 65-76, 2002