Frontiers of medical and biological engineering : the international journal of the Japan Society of Medical Electronics and Biological Engineering最新文献

{"title":"Parallel recording of physical activity on commercial Holter recorders.","authors":"K Sekioka,&nbsp;H Takaba,&nbsp;T Nakano","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>To accurately interpret heart rate variability (HRV) including circadian rhythm from Holter ECG, the simultaneous assessment of physical activity, which significantly affects HRV, is essential. In this study, to obtain this simultaneous assessment, the fundamental problems in implementing an accelerometer in a commercial Holter recorder were studied. In a treadmill exercise, three axial outputs of an accelerometer showed highly linear correlations with the running speed (correlation coefficient; vertical 0.94, forward-backward 0.97, sideways 0.97, three-dimensional amplitude 0.96, n = 8). The vertical acceleration showed a slightly sigmoidal increase with speed. Against a slope change, no significant increase in acceleration was observed except in the forward-backward direction. Individual calibration was found to be needed for the accurate estimation of physical load from body acceleration. A simplified calculation with the sum of the three axial absolute values correlated highly with the three-dimensional (3D) acceleration which shows the most reliable response to motions in any direction (r = 0.98, the slope of the regression line = 0.97) and, with this relation, the estimated 3D amplitude showed a sufficient degree of agreement. This substituted calculation was used in the Holter recordings. To know the posture of subjects, a piezoresistive accelerometer with the function of clinometer was used in another study. From played-back Holter recordings, the R-R interval and body acceleration were simultaneously sampled. The serial changes of both the power spectra of HRV and the body acceleration were observed over a 24 h period. Some cases with an abnormally reduced high-frequency component (HF) of HRV at night or an unusually high HF in the daytime were explained by physical conditions estimated with the accelerometer. The simultaneous assessment of patients' physical state by the present method provides the accurate interpretation of circadian rhythm in HRV.</p>","PeriodicalId":77139,"journal":{"name":"Frontiers of medical and biological engineering : the international journal of the Japan Society of Medical Electronics and Biological Engineering","volume":"8 4","pages":"253-68"},"PeriodicalIF":0.0,"publicationDate":"1997-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"20713304","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Quantitative assessment of the spatial distribution of low attenuation areas on X-ray CT using texture analysis in patients with chronic pulmonary emphysema.","authors":"M Mishima,&nbsp;Y Oku,&nbsp;K Kawakami,&nbsp;N Sakai,&nbsp;M Fukui,&nbsp;T Hirai,&nbsp;K Chin,&nbsp;M Ohi,&nbsp;K Nishimura,&nbsp;H Itoh,&nbsp;M Tanemura,&nbsp;K Kuno","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>An automated and quantitative assessment of the spatial distribution of low attenuation areas (LAA) on X-ray CT was performed using texture analysis in chronic pulmonary emphysema (CPE) patients. LAA was defined as those areas having a density less than the mean minus one SD of the control (-960 HU). The probability of change from non-LAA to LAA between a given pair of pixels with horizontal intervals of i pixels (RNi) was evaluated, because this reflects the interaction between LAA and non-LAA regions with different resolutions. The relationship between the percentage area of the LAA over the total area of the entire lung field (LAA%) was subsequently estimated. The RNi increased sharply as the i value increased from 1 to 5, but then almost became a plateau for i values larger than 5. This suggests that the fundamental structures in the LAA areas ranged from 1 x 1 to 5 x 5 pixels in size. RN1-LAA% and RN5-LAA% plots produced curves which were convex, with peak values at approximately 50 LAA% of 0.09 and 0.18, respectively. In the RN5/RN1-LAA% plot, the RN5/RN1 ratio remained constant at 2.0 regardless of the LAA%. A random process simulation was performed to determine the patterns of LAA proliferation if the spatial distribution of the LAA units was random. When the unit size was kept constant, the results of the simulation did not fit the empirical relationship between the LAA% and the three parameters (RN1, RN5 and RN5/RN1). The simulation provided the best-fitting curves when the unit size of the LAA increased in proportion with the LAA%, starting from a 1 x 1 pixel size increasing at a ratio 1 x 1/(5 LAA%). This suggested that the LAA units do not proliferate randomly in spatial orientation at a fixed unit size, but rather spread throughout the whole lung field in a congregated form whilst increasing their unit size. Thus, it may be concluded that healthy lung tissues near emphysematous lesions have a high probability of suffering from emphysema in the future. This may be due to a direct effect of the neighboring emphysematous lesion or due to a pathologic change in the larger bronchii which dominate both the healthy tissues and the emphysematous lesions.</p>","PeriodicalId":77139,"journal":{"name":"Frontiers of medical and biological engineering : the international journal of the Japan Society of Medical Electronics and Biological Engineering","volume":"8 1","pages":"19-34"},"PeriodicalIF":0.0,"publicationDate":"1997-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"20036192","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Positional reproducibility of the patient's head normalized by a robotized chair-based automatic head-positioning system, Racs-N.","authors":"Y Nakamura,&nbsp;T Hayashi,&nbsp;T Takeda,&nbsp;K Katoh,&nbsp;M Miyakawa,&nbsp;M Itoh","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>With a view to normalization of the head orientation without the use of a fixation jig for the measurement of jaw movement employing an X-ray television, we have been developing an automatic head-positioning system, Racs-N, consisting of a head-position sensor and a robotized chair. The head position is monitored in 6 degrees of freedom (d.o.f.) by using a position-sensitive detector (PSD) camera-based photostereometry. If they are incorrect, the robotized chair rectifies them automatically by adjusting the position and orientation of the head support in 5 d.o.f. (except the vertical position). The rectified position, however, has a certain margin of error, due to the mobility of the head relative to the head support. To improve this, we employed an iterative correction in that the positioning is repeated until the determined position converges. In experiments employing several subjects, this particular correction was verified to converge by more than six iterations and to be effective for the reduction of head-position errors.</p>","PeriodicalId":77139,"journal":{"name":"Frontiers of medical and biological engineering : the international journal of the Japan Society of Medical Electronics and Biological Engineering","volume":"8 3","pages":"179-96"},"PeriodicalIF":0.0,"publicationDate":"1997-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"20370981","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Long-term results of hydroxyapatite application in the treatment of periodontal osseous defects.","authors":"Z Knychalska-Karwan,&nbsp;A Kaczmarczyk-Stachowska,&nbsp;A Slosarczyk,&nbsp;E Stobierska,&nbsp;Z Paszkiewicz","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>The aim of the present study was to evaluate in long-term clinical trials the effectiveness of hydroxyapatite (HA) bioceramics employed in dentistry in the treatment of periodontal osseous defects. The technology of obtaining the studied HA was developed at the Faculty of Material Science and Ceramics, University of Mining and Metallurgy, Cracow, Poland. A population of 90 patients was subjected to implantation of HA granules. The results of initial and final investigations based on periodontal indices, determination of osseous defects depth and X-ray studies were compared. The follow-up was 6 and 12 months, 2, 3 and as much as 4 years. All the studied parameters showed a significant improvement that was confirmed by statistical evaluation. Ceramic HA was found to be a fully and totally useful material in the reconstruction of periodontal defects. As demonstrated by X-ray studies, the reconstruction of osseous defects proceeded faster within the first 2 years and subsequently the process became slower.</p>","PeriodicalId":77139,"journal":{"name":"Frontiers of medical and biological engineering : the international journal of the Japan Society of Medical Electronics and Biological Engineering","volume":"8 4","pages":"239-52"},"PeriodicalIF":0.0,"publicationDate":"1997-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"20713303","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Ambulatory system to aid in decision making and risk stratification in postinfarction patients.","authors":"M Pascual,&nbsp;M A González,&nbsp;J Márquez Montes,&nbsp;I Lozano,&nbsp;C H Salvador","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>Knowledge of the clinical and electrophysiological features of certain cardiovascular risk groups, the adaptation and specialization of clinical protocols, the availability of tools to make determinations for use in patient follow-up and to assess the efficacy of the treatments applied, and the proper processing of different parameters can aid in decision making, leading to the application of a given therapeutic approach, and can facilitate the performance of group and multicenter studies. To address these needs, a simple, low-cost, portable ECG processing system has been designed that complements the current techniques for managing patients with ischemic heart disease and nonmalignant ventricular arrhythmias. This system, consisting of an electrocardiograph and a laptop PC, determines the following parameters on the basis of the ECG: incidence of arrhythmia, heart rate variability, QT dispersion, ECG criteria for ventricular hypertrophy and late potentials. Left ventricular ejection fraction and diastolic function (according to Doppler ultrasound) and other basic epidemiological parameters are typed in. Moreover, the system integrates these parameters, which have usually been considered separately, to arrive at second-level indicators with a greater predictive capacity during the long-term follow-up of patients with ischemic heart disease and ventricular arrhythmias, thus providing an idea of the risk of mortality and the onset of arrhythmic events and allowing risk stratification in this patient population. Finally, the system includes a database of all the patients analyzed, with tools that make it possible to follow the course of their disease and to assess the efficacy of the treatments applied.</p>","PeriodicalId":77139,"journal":{"name":"Frontiers of medical and biological engineering : the international journal of the Japan Society of Medical Electronics and Biological Engineering","volume":"8 4","pages":"269-86"},"PeriodicalIF":0.0,"publicationDate":"1997-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"20713855","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Automatic head positioning system using PSD-equipped camera-based photostereometry and a 5-degree-of-freedom robotized chair: calibration and accuracy verification.","authors":"Y Nakamura,&nbsp;T Hayashi,&nbsp;T Takeda,&nbsp;K Katoh,&nbsp;M Miyakawa,&nbsp;M Itoh","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>In measurements of jaw movements employing an X-ray television, the orientation of the patient's head must be normalized relative to the measuring device. To avoid interferring with natural jaw movements caused by using a positioning jig, we have developed an automatic head positioning system consisting of a head position sensor and a robotized chair. The position and orientation of the head is monitored by detecting the three-dimensional positions of four non-coplanar LED markers mounted on the head, by means of a set of two photoelectronic cameras. If they are incorrect, the head is moved into the required position, using a 5-degree-of-freedom robotized chair. To accomplish this accurately, the positional relations of system components must be determined precisely. This paper proposes a least-square technique of calibrating the relationship between the position sensor and the chair. Consequently, accurate positioning is achieved. Accuracy verification studies revealed that overall positioning errors lay within 2.42 mm and 1.28 degrees with respect to the position and orientation, respectively, if the markers are secured to the head support of the chair.</p>","PeriodicalId":77139,"journal":{"name":"Frontiers of medical and biological engineering : the international journal of the Japan Society of Medical Electronics and Biological Engineering","volume":"8 1","pages":"47-63"},"PeriodicalIF":0.0,"publicationDate":"1997-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"20036194","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Effects of resistive load on the phase difference between chest and mouth flow in patients with chronic obstructive pulmonary disease.","authors":"M Mishima,&nbsp;K Higashiya,&nbsp;K Kawakami,&nbsp;N Sugiura,&nbsp;N Sakai,&nbsp;T Hirai,&nbsp;Y Oku,&nbsp;K Chin,&nbsp;M Ohi,&nbsp;K Kuno","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>The influence of the resistive load on the phase difference (PD) between chest wall and mouth flow in patients with chronic obstructive pulmonary disease (COPD) was investigated, and the factors that induce an enlargement of the PD were assessed. After a resistance tube (R = 2.8 hPa/l/s) was applied to the mouth of the subjects, the PDs increased significantly both in normal (pre: 2.20 +/- 0.89, post: 5.60 +/- 2.04, P < 0.01) and in COPD (pre: 10.86 +/- 3.81; post: 13.12 +/- 3.64, P < 0.01). A significant correlation between the airway resistance and PD was noted (r = 0.730, P < 0.001). These results suggest that airway resistance is an important determinant for the PD. The predicted phase difference (PD') was then calculated by the Runge-Kutta method, using the measured chest flow, the time domain functions of airway resistance and the thoracic gas volume during a respiratory cycle, assuming that the respiratory system was a single compartment. The PD/PD' at pre-resistive load was significantly larger in COPD than in normal subjects (normal: 1.03 +/- 0.11; COPD, 1.45 +/- 0.19, P < 0.01), whereas the PD/PD' at a post-resistive load was significantly smaller than at the pre-resistive load in COPD patients. These results agree well with the two parallel or serial compartment model with inhomogeneous airway resistance, where the mechanical property of the partitioning tissue between the two compartments was taken into account. The pattern of the increase in the work energy consumed within the airway lumen calculated from this model was almost the same as for PD. Thus, we conclude that the PD may be a good index of the overload of the respiratory movement and available to predict muscle fatigue in COPD patients.</p>","PeriodicalId":77139,"journal":{"name":"Frontiers of medical and biological engineering : the international journal of the Japan Society of Medical Electronics and Biological Engineering","volume":"8 1","pages":"1-18"},"PeriodicalIF":0.0,"publicationDate":"1997-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"20036191","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Spectrum analysis of respiratory sound: application to smokers and non-smokers.","authors":"A A Kamal","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>Previous studies have indicated that respiratory sound signals may contain information useful in the detection of lung diseases. In this study, measurement and recordings of respiratory sound signal segments were obtained in normal subjects (non-smokers) and smokers in both inspiration and expiration phases. By using the autoregressive (AR) method, it is possible to produce power spectra of respiratory sound signals in inspiration and expiration phases for smokers and non-smokers of each group. The selection of the AR model order of the respiratory sound signals is achieved using Akaike criterion. The AR model order of 9 is required for completely described respiration sound signal segments in inspiration and expiration phases for both groups. The power spectra in the smoker group show larger distinct peaks at lower frequencies as well as more harmonics in both inspiration and expiration phases compared to the power spectra of the non-smoker group. Another diagnostic indicator was derived from the relative position of poles of the AR model of respiratory sound signals. In all smokers it was found that the first, third and fourth poles were closer to a unit circle than those in non-smokers (P < 0.01). It seems that the use of these indicators may be useful as early diagnostic tool for lung diseases.</p>","PeriodicalId":77139,"journal":{"name":"Frontiers of medical and biological engineering : the international journal of the Japan Society of Medical Electronics and Biological Engineering","volume":"8 3","pages":"165-77"},"PeriodicalIF":0.0,"publicationDate":"1997-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"20370980","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Standardization of low attenuation area versus total lung area in chest X-ray CT as an indicator of chronic pulmonary emphysema.","authors":"M Mishima,&nbsp;T Hirai,&nbsp;Z Jin,&nbsp;Y Oku,&nbsp;N Sakai,&nbsp;Y Nakano,&nbsp;H Sakai,&nbsp;K Chin,&nbsp;M Ohi,&nbsp;K Kawakami,&nbsp;K Shimada,&nbsp;H Itoh,&nbsp;K Yamaguchi,&nbsp;T Sawa,&nbsp;K Kuno","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>We examined the methods for measuring the LAA% (100 x low attenuation area/total lung area) on thoracic X-ray CT scans in order to develop a useful indicator of chronic pulmonary emphysema (CPE). First, we modified the method for calculating the LAA% to be applicable by the programming tool installed in a commercially available CT machine in order to minimize manual procedures. This new method proved to be applicable in all CT machines produced after 1987. Second, we examined the difference in the Hounsfield Unit (HU) between different CT machines using two kinds of phantoms. One phantom was composed of Styrofoam, which has a density similar to the low attenuation areas. The other phantom was composed of Styrofoam and water, which has a density similar to the lung. We proved that the difference of LAA% with the correct value was 5% at maximum among four different CT machines. Thus, the phantom developed in the present study may play an important role in the standardization of HU. Finally, the possibility of decreasing the X-ray levels was examined. Twenty-five percent of the standard electrical current provided the same LAA% in cases where the subject was an established CPE patient, whereas the LAA% was overestimated in subjects with a normal LAA% value. However, a correction using a linear regression equation may be possible in the latter cases. It may be concluded that LAA% analysis can easily be performed in many city hospital, without much investment of manual procedures or any corrections to the HU levels between different CT machines. This method may be useful as a routine follow up for CPE patients because of the smaller irradiated dose given when using a CT machine.</p>","PeriodicalId":77139,"journal":{"name":"Frontiers of medical and biological engineering : the international journal of the Japan Society of Medical Electronics and Biological Engineering","volume":"8 2","pages":"79-86"},"PeriodicalIF":0.0,"publicationDate":"1997-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"20200143","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Developmental changes in functional EEG asymmetry: a multivariate autoregressive modeling approach.","authors":"K Sato,&nbsp;T Ogawa,&nbsp;M Wada,&nbsp;M Ishiguro","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>To investigate the functional asymmetry of the electroencephalogram (EEG) in the developing brain, we analyzed quantitatively the different components of simulated EEG (SEEG) in a model before and after cutting off the intercerebral interaction. Original EEG (OEEG) recordings were obtained from 374 normal children aged 3-12 years. The SEEGs were computed from the OEEG after applying 'ARdock', a new multivariate autoregressive (AR) modeling method. Subsequently, the univariate AR and component analysis was applied on OEEG and SEEG. The F value was computed from Mahalanobis' distance between both AR coefficients of component activities for age, EEG derivation and frequency band. Our analysis showed developmental lateralities in the alpha band at the frontal pole in 5 and 12 year old children, and at the central region in 8 and 11 year old children. Our results suggest that the intercerebral interactions develop at approximately 5 years of age at the left frontal pole during the period of maturation of alpha band activity and after 8 years of age when it replaced theta band activity. The present method of analysis may have a wide clinical application in the analysis of normal and abnormal EEGs.</p>","PeriodicalId":77139,"journal":{"name":"Frontiers of medical and biological engineering : the international journal of the Japan Society of Medical Electronics and Biological Engineering","volume":"8 2","pages":"109-22"},"PeriodicalIF":0.0,"publicationDate":"1997-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"20200145","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}