Technology and Health Care - Volume 5, issue 5

Authors: Carruth, J.A.S.

Article Type: Research Article

DOI: 10.3233/THC-1997-5501

Citation: Technology and Health Care, vol. 5, no. 5, pp. 335-345, 1997

Authors: Amoussou-Guénou, K.M. | Squitiero, B. | Voutay, M. | Labat, B. | Rusch, Ph.

Article Type: Research Article

Abstract: The purpose of this study was to identify a parameter allowing the standardization of the Cell Transit Analyzer (CTA) in order to study the individual deformability of each explored Red Blood Cell (RBC). Using theoretical arguments based on the principle of the CTA, we calculated the thickness “x ” of the crown of fluid surrounding each RBC during its entry phase into the micropore. A mathematical equation (x = 62.5 / | d U | ) was established between the difference of potential (U , mV) that occurs during this phase and the corresponding thickness (“x ”, μ …m) of the crown. By exploring fresh control RBCs of healthy subjects and assuming that the rigid RBCs proportion in a fresh blood sample of healthy subject is less than 3.5%, we performed a thresholding of “x ” to distinguish rigid RBC from deformable ones. That thresholding was necessary to stamp the variability of counts linked to polycarbonate filters (PF) used to carry out measures. According to the PF, the value of the threshold “T x ” provided by the thresholding ranged between 0.222 and 0.246 μ m. Using the values of “T x ”, we counted approximately 10–25% rigid RBCs in the pathological samples of four patients with sickle cells SS disease and of one diabetic patient with splenomegaly. We observed in addition that the percentages of rigid RBCs counted after thresholding are identical from a filter to another one with an absolute error less than 2% in fresh RBCs (normal or pathological) samples. We concluded that the method of standardization by thresholding presented here could be used in clinic routine to count the rigid RBCs percentage contained in a given sample. Show more

Keywords: CTA, standardization, cellular deformability, RBCs, rigid subpopulation

DOI: 10.3233/THC-1997-5502

Citation: Technology and Health Care, vol. 5, no. 5, pp. 347-357, 1997

Authors: Hadjileontiadis, Leontios J. | Panas, Stavros M.

Article Type: Research Article

Abstract: The use of higher-order statistics for diagnostic assessment and characterisation of lung sounds is presented in this article. The parametric approach of bispectrum estimation, which is a third-order spectrum, based on a non-Gaussian white noise driven autoregressive (AR) model, reveals information about lung sounds that is not contained in the ordinary power spectrum, such as the degree of nonlinearity and deviations from normality. Characterisation of source and transmission of lung sounds is achieved using an AR model based on third-order statistics. Furthermore, harmonic analysis of lung sounds is combined with the bicoherence index in order to obtain information regarding possible …quadratic phase coupling among harmonic components of musical lung sounds. Experiments have shown that higher-order statistics can offer reliable evaluation of lung sounds characteristics, since their general properties and robustness in noiseless or noisy environments (lung sounds contaminated with additive symmetrical noise, e.g., Gaussian) proved to have superior advantages in objective analysis of pulmonary dysfunction. Show more

Keywords: Higher-order statistics, lung sounds, bispectrum, bicoherency, AR modelling, source characterisation, sound transmission

DOI: 10.3233/THC-1997-5503

Citation: Technology and Health Care, vol. 5, no. 5, pp. 359-374, 1997

Authors: Guglielmi, G. | Cammisa, M. | De Serio, A. | Giannatempo, G.M. | Bagni, B. | Orlandi, G. | Russo, C.R.

Article Type: Research Article

Abstract: In a multicenter evaluation the precision and stability of single slice peripheral Quantitative Computed Tomography (pQCT) systems were assessed. Compared to central Europe the peripheral QCT device is also widely used in the Italian health care system. Phantoms were measured frequently on each machine in four pQCT scanners over a two-year period using an identical automated software program. Intrasite and intersite phantom mineral densities, expressed in units of mg/cm3 , were analyzed and examined. The short and long term precision were estimated from the consistency of these measurements using the root mean square error and expressed as coefficient of variation …in percent (% CV). Short term precision was good (mean intrasite coefficient of variation (CV) 0.21 ± 0.056 standard deviation (SD)). Intersite measurements of a single phantom revealed differences between machines of the same type of not more than 2.9 mg/cm3 . At four sites frequent phantom measurements revealed a mean CV of 0.18% (range 0.12–0.28). No significant changes in the regression slopes (drift of the machine versus time) were observed. We conclude that the in vitro precision and stability of the single slice pQCT systems are sufficiently high and unlikely to negatively affect the in vivo precision. Show more

Keywords: Bone densitometry, peripheral quantitative computed tomography, quality assurance

DOI: 10.3233/THC-1997-5504

Citation: Technology and Health Care, vol. 5, no. 5, pp. 375-381, 1997

Authors: Toumoulin, C. | Mao, F.

Article Type: Research Article

Abstract: This work is aimed at the extraction of vascular structures using perceptual grouping methods. The approach is based on structural feature matching, between images in the time sequence. These features correspond to junctions (or bifurcation points) and are paired by means of a local criteria. A global refinement procedure is then applied by means of a relaxation scheme. The feature trajectories over the entire image sequence are examined to further build sets of vascular segments, which better describe vascular branches. The resulting performances are exemplified on a standard biplane coronarographic examination.

Keywords: Digital Subtraction Angiography (DSA), cardiology, perceptual grouping, relaxation methods, spatio-temporal matching

DOI: 10.3233/THC-1997-5505

Citation: Technology and Health Care, vol. 5, no. 5, pp. 383-406, 1997